Full opinion text
Opinion GEORGE, C. J. In this case we address a challenge to an employment-related drug testing program adopted by the City of Glendale in 1986. Under the program in question, all individuals who conditionally have been offered new positions with the city (both newly hired persons and current city employees who have been approved for promotion to a new position) are required to undergo urinalysis testing for a variety of illegal drugs and alcohol as part of a preplacement medical examination that the city traditionally has conducted prior to hiring or promotion. The drug testing requirement applies to all of the city’s employment positions, and is imposed without regard to whether the city has any basis for suspecting that a particular applicant for employment or promotion currently is abusing drugs or alcohol. The trial court concluded that the city could not lawfully impose a drug testing requirement for all city positions in either the preemployment or prepromotion context, and then undertook the substantial task of reviewing detailed job descriptions of 80 job categories (many of which included a number of separate job classifications) and, with regard to each category and classification, balancing the intrusion upon reasonable expectations of privacy against the governmental interests served by drug testing. The trial court ultimately determined that the challenged drug testing program was invalid as to classifications falling within 36 of the designated categories, and valid as to the remaining positions. On appeal, the Court of Appeal agreed with the trial court that the city could not require drug testing for all city positions, in either the preemployment or the prepromotion setting, but concluded that the trial court improperly had approved drug testing for a significantly larger group of employment positions than was constitutionally permissible. We granted review to determine the validity of the city’s drug testing program under the statutory and constitutional provisions relied upon by plaintiff. As we shall explain, we conclude that the across-the-board drug testing program here at issue is invalid as applied to current employees who have been conditionally approved for promotion, but is valid as applied to job applicants. I A From 1983 to 1985, the city’s personnel department observed an increase in the number of city employee disciplinary cases in which substance abuse appeared to be a significant factor, as well as an increase in the number of city employees who voluntarily referred themselves for treatment for substance abuse. In response, the city instituted a two-month pilot project (beginning in November 1985) under which drug testing was conducted on all applicants for city employment. Of the 48 applicants who were tested during the pilot project, 10 (approximately 21 percent) tested positive for drugs. Thereafter, in mid-1986, the city’s civil service commission adopted the drug and alcohol screening program that is challenged in this case. For at least 10 years prior to the 1986 adoption of the program, the city had required every applicant who had been conditionally approved for hiring or promotion to undergo a preplacement medical examination paid for by the city and conducted at the medical offices of a city-designated physician. As part of the preplacement medical examination, applicants were required to provide a urine sample for analysis for various medical conditions. In adopting the drug and alcohol testing program here at issue, the civil service commission approved the addition of a drug and alcohol screening component to this preexisting preplacement medical examination process. The record discloses that the medical examination and drug and alcohol screening process operates in the following manner. Applicants for employment or promotion are notified in the city’s employment bulletin (which announces job openings) that, as part of the selection process, a medical examination, including drug and alcohol screening, is required of all applicants. After an applicant has completed the initial, substantive portion of the application process (consisting, typically, of written and/or oral examinations, performance tests, background and reference checks, etc.), and has been selected by the city for employment or promotion, the applicant is notified that his or her hiring or promotion is conditioned upon successful completion of a preplacement medical examination that includes a drug and alcohol screening component. The personnel department refers all successful applicants to Dr. Robert Newhouse, a Glendale physician, for medical examination and drug testing. The record indicates that Dr. Newhouse had conducted preplacement medical examinations for the city for 10 years prior to its adoption of the drug testing program. The medical examination and drug and alcohol screening are conducted at Dr. Newhouse’s medical offices. When an applicant arrives at the offices, he or she is asked by a medical employee to sign a written form, consenting to a medical examination and to drug and alcohol testing, and authorizing the release of the test results to the city. The form also asks the applicant to list all medications and drugs that he or she currently is taking, and informs the applicant that a positive result on the drug or alcohol screening test, absent a valid legal explanation for the presence of such drug or alcohol, will result in disqualification from the hiring or promotion process. Applicants who refuse to sign the consent form or to undergo the screening process are considered medically disqualified for employment or promotion, and are advised that the disqualification will remain in effect for the applicant’s entire period of eligibility for the position in question. After the consent form has been completed and signed, the testing process begins. At the time the city added the drug testing component, it instituted a number of measures designed to prevent fraud or adulteration in the drug testing procedure. First, the applicant is provided a hospital gown to wear and is asked to undress down to his or her underwear. A medical employee then furnishes the applicant an empty, sealed, sterile container, and the seal is broken in the presence of the applicant. Thereafter, a medical employee accompanies the applicant to a restroom and stands in a cubicle next to the applicant’s cubicle while the applicant provides a urine sample; the medical employee does not visually observe the urination process. As additional safeguards against potential fraud, blue colored water is used in the toilet bowl to prevent adulteration of the urine sample, and the medical employee checks the temperature of the sample that the applicant has provided. If the urine sample is cold, the applicant is requested to provide another sample. After the applicant has given the urine sample to the medical employee, the sample is tested (in the applicant’s presence), using a “dipstick,” to determine the presence of blood, sugar, or protein in the urine, as a screen for medical problems. Thereafter, the container is closed and sealed with evidence tape, and the applicant and medical employee both sign a “chain of custody” slip that is placed in a laboratory envelope along with the sample. The applicant subsequently undergoes the remainder of the medical examination, which generally consists of at least the taking of a complete medical history from the applicant, a general physical examination, audiometric testing, and tuberculosis skin testing. Thereafter, the laboratory envelope containing the applicant’s urine sample is sent to an independent, certified testing laboratory, which examines the sealed sample for signs of tampering and assigns a serial number to the sample to avoid identifying the applicant by name. While the sample is at the laboratory, a positive chain of custody is kept at all times, and the laboratory is secured by magnetically controlled doors. At the laboratory, the urine sample is tested for the following substances: (1) amphetamines and methamphetamines (including “speed” and “crystal”), (2) benzodiazepines (including Valium, Librium, Oxazepam, Serex, Dalmane), (3) barbiturates (including Amobarbital, Butabarbital, Pentobarbital, Phenobarbital, Secobarbital), (4) cocaine, (5) methadone, (6) methaqualone (i.e., Quaalude), (7) opiates (including codeine, heroin, morphine, hydromorphone, hydrocodone), (8) phencyclidine (PCP), (9) “THC” (marijuana), and (10) alcohol. The sample initially is tested by an enzyme immunoassay (EMIT) test. If that test discloses a positive finding, the sample is tested by a gas chromatography/mass spectrophotometry (GCMS) test. If the second test is negative, the overall test result is considered negative and reported as such by the laboratory. Any sample that has tested positive is retained by the laboratory for 12 months, to permit retesting in connection with any administrative appeal the applicant may file. The results of the laboratory testing are set forth in a written report to Dr. Newhouse. Dr. Newhouse reviews the results in conjunction with the consent form that the applicant has completed (on which the applicant has disclosed the medications that he or she currently is taking), determines whether the test has revealed the presence of drugs for which the applicant has no legitimate medical explanation, and reports his conclusion to the director of personnel. All test results, like all other medical records, are treated as confidential and kept in a confidential medical file. The director of personnel testified that the information is not disclosed to any law enforcement agency. If the test reveals the presence of drugs for which the applicant has no legitimate medical explanation, the applicant is disqualified from hiring or promotion, and remains ineligible for the period during which the “eligibility list” for the job in question is in force. A disqualified promotional applicant, currently employed by the city in another position, is referred to a mandatory assistance program that includes group counseling and a wide variety of educational programs. Applicants for hiring or promotion who are disqualified as a result of the drug testing program may appeal to the city’s civil service commission, pursuant to procedures governing an applicant’s disqualification for other medical conditions. If the applicant or the civil service commission requests retesting of the sample in connection with such an administrative appeal, and the applicant agrees that the results of the retesting may be released to the city’s personnel division, the retesting, by gas chromatography, is performed at a laboratory selected by the applicant from a list of three laboratories designated by the city. If the results of the second drug screen are negative, Dr. Newhouse reviews the results and recommends either qualifying or disqualifying the applicant; if the results are positive, the initial disqualification remains in effect. If the applicant continues to contest a disqualification, the civil service commission may reject the appeal or direct that a third drug screen be conducted on the initial sample by another laboratory. If the third test is negative, Dr. Newhouse reviews the results and makes a recommendation to the civil service commission, which may find the applicant either eligible or disqualified. B Shortly after the city’s adoption of the drug testing program, plaintiff Lorraine Loder, a taxpayer, instituted the present taxpayer’s suit to enjoin further expenditure of public funds relating to the drug testing program. (See Code Civ. Proc., § 526a.) The complaint alleged that the drug testing program violated the provisions of a California statute, the Confidentiality of Medical Information Act (Civ. Code, § 56 et seq.), and also violated the provisions of the federal and state Constitutions guaranteeing the right to be free of unreasonable searches and seizures, and the right of privacy. (U.S. Const., 4th Amend.; Cal. Const., art. I, § 1.) After considering briefs submitted by the parties with regard to the appropriate constitutional analysis to be applied in this context, the trial court concluded that it was “mandated by applicable law, as handed down by the United States Supreme Court and other sources, to engage in a constitutional analysis as to each category of positions placed in issue by the parties.” In light of this conclusion, the court directed the parties to prepare a joint statement describing each of the numerous job categories to which the drug testing program applied, including a discussion of factors affecting an employee’s reasonable expectation of privacy and the particular governmental interests supporting such testing. The resulting joint statement was approximately 500 pages in length. In addition to submitting the joint statement, the parties introduced testimony from city officials and expert witnesses concerning the background and purpose of the drug testing program, the harmful effects of drug use in the employment context, and alternative methods—other than urinalysis testing—that may be available for detecting and dealing with the drug use problem in the employment context. After considering the material presented by the parties and the numerous federal and state decisions evaluating drug testing programs, the trial court, in a 250-page opinion, concluded that the Glendale drug testing program was valid as to numerous job classifications but invalid as to others. In reaching its conclusion, the trial court initially considered the constitutional validity of the drug testing program under the federal and state Constitutions, looking to prior federal and state cases that had identified a variety of factors that could justify drug testing for particular job classifications in the absence of individualized suspicion—for example, whether the position was closely involved with public safety, related to drug interdiction, or involved access to highly sensitive or classified information—as well as other factors that could affect the reasonable expectation of privacy of persons employed in particular positions. After balancing the governmental interests supporting drug testing against the employees’ reasonable expectations of privacy with regard to each job classification, the trial court ultimately concluded that the city’s drug testing program was invalid, in both the preemployment and prepromotion contexts, as to specified positions in 36 of the 80 job categories to which the policy applied, but valid as to the remaining positions. Thus, for example, the trial court found the drug testing program constitutionally invalid as applied to city attorneys and their secretaries, library and city clerk personnel, clerks and stenographers, meter readers, and finance and administrative services personnel, but valid as applied to police, fire, and jail personnel, waste management and sanitation workers, health service personnel, mechanics and repair workers, and power and water department personnel. With regard to plaintiff’s statutory argument, the trial court concluded that the drug testing program did not violate the provisions of the Confidentiality of Medical Information Act (Civ. Code, § 56 et seq.). The trial court issued an injunction prohibiting the city from applying the challenged drug testing program to those job categories as to which it had found the testing constitutionally impermissible. At the same time, the trial court expressly stated that the injunction applied only to the drug testing aspects of the city’s examination process and that the city was “not prohibited from conducting the remainder of the existing physical examinations as to [such job categories], including the taking of urine samples from the applicants or employees for purposes other than the detection of illegal drug use, including for ascertainment of medical condition and physical fitness.” C Both parties appealed from the judgment of the trial court. The city contended that the trial court should have found the drug testing program permissible with regard to all job classifications, while plaintiff contended that the trial court’s injunction was too limited and should have applied to additional job classifications. The Court of Appeal agreed with the trial court that a drug testing program that applied to all employment positions is impermissible in both the preemployment and the prepromotional contexts, but the appellate court concluded that, in balancing the privacy interests of employees against the governmental interests served by drug testing, the trial court improperly had upheld the validity of the drug testing program with regard to many job classifications as to which the city had failed to demonstrate a sufficiently compelling justification. As the Court of Appeal interpreted the governing federal and state constitutional decisions, the city’s suspicionless drug testing program was valid “only as to positions in which the regular duties involve some special and obvious physical or ethical demand, and the compromise of the employee’s ability to meet such demands could have an immediate disastrous consequence upon public safety or security” (italics added). The Court of Appeal then determined that the trial court had approved drug testing with respect to many job classifications that did not pose safety or security concerns of this magnitude. Finally, the Court of Appeal held that even with regard to those employment positions that satisfied its stringent standard, drug testing may be required only “(1) upon initial employment in the job category, whether by hire or promotion; and (2) after a job offer has been made; and (3) if the test is conducted in a manner which does not violate the Americans With Disabilities Act, i.e., without requiring disclosure of any medical history information (including drugs which the applicant is taking upon advice and/or prescription of a medical doctor) which is not relevant to the applicant’s ability to perform the job; and (4) if the sample is collected in a manner which does not intrude unnecessarily upon the right to personal privacy; and (5) if an initial positive test is confirmed by a second test regarded as reliable by the relevant scientific community.” (Fns. omitted.) The Court of Appeal reversed the portion of the judgment that permitted drug testing “as to specified [job] categories where inconsistent with the views expressed” in the Court of Appeal opinion, and remanded the matter to the trial court “for the sole purpose of further limiting those job titles as to which preemployment and promotional drug testing may be conducted.” The city sought review of the Court of Appeal’s decision, challenging both the constitutional standard embraced by the Court of Appeal and that court’s application of the standard to the numerous job classifications at issue in this case. We granted review to consider the validity of the city’s drug testing program under the applicable statutory and constitutional provisions. II As noted at the outset, plaintiff’s challenge to the city’s drug testing program here at issue rests on both statutory and constitutional grounds. Pursuant to traditional principles of judicial restraint, we turn first to plaintiff’s statutory claim because, were that claim meritorious, there would be no need to reach plaintiff’s constitutional contentions. (See Ashwander v. Valley Authority (1936) 297 U.S. 288, 347 [80 L.Ed. 688, 711, 56 S.Ct. 466] (conc. opn. by Brandeis, J.).) Plaintiff contends that the city’s drug testing program violates a provision of California’s Confidentiality of Medical Information Act. (Civ. Code, § 56 et seq.) In general, this legislation, enacted in 1981, is intended to protect the confidentiality of individually identifiable medical information obtained from a patient by a health care provider, while at the same time setting forth limited circumstances in which the release of such information to specified entities or individuals is permissible. (See, e.g., Heller v. Norcal Mutual Ins. Co. (1994) 8 Cal.4th 30 [32 Cal.Rptr.2d 200, 876 P.2d 999].) To provide such protection, the act specifies that “[n]o provider of health care shall disclose medical information regarding a patient of the provider without first obtaining an authorization . . .” (Civ. Code, § 56.10, subd. (a)), and then sets forth, in some detail, the requirements of a valid authorization for the release of medical information “by a provider of health care” (id., § 56.11) or by an employer (id., § 56.21). The record in the present case indicates that the city treats the results of the drug testing program with the same degree of confidentiality as all other confidential medical information obtained as a result of its medical examination of job applicants and employees, retaining the information in confidential medical files and disclosing the results of the testing only to the city personnel director. Plaintiff does not contend that the manner in which the city handles or maintains drug test results violates the provisions of the Confidentiality of Medical Information Act relating to an employer’s duty to protect against the unauthorized disclosure or use of confidential medical information. (Civ. Code, § 56.20, subds. (a), (c).) Instead, plaintiff contends that the drug testing program violates the act insofar as the program automatically disqualifies from employment or promotion any employee who refuses to sign a form (tendered to an applicant prior to testing), authorizing the physician who conducts the drug testing to inform the city of the results of the testing. Plaintiff relies, in this regard, upon Civil Code section 56.20, subdivision (b), which provides in full: “No employee shall be discriminated against in terms or conditions of employment due to that employee’s refusal to sign an authorization under this part. However, nothing in this section shall prohibit an employer from taking such action as is necessary in the absence of medical information due to an employee’s refusal to sign an authorization under this part.” (Italics added.) Plaintiff contends that by disqualifying applicants who refuse to authorize disclosure to the city of the results of city-mandated drug testing, the program impermissibly “discriminates” against applicants who “refus[e] to sign an authorization,” in violation of Civil Code section 56.20, subdivision (b), and that the city has failed to establish that its disqualification of such applicants from employment or promotion is “necessary” within the meaning of this subdivision. Plaintiff contends, in this regard, that the reference in section 56.20, subdivision (b), to “necessary” “should be defined to require an employer to have a compelling reason to act in the absence of information and should further require that the employer had no reasonable, less intrusive alternative.” In our view, plaintiff’s proposed interpretation of Civil Code section 56.20, subdivision (b), is untenable. An employer “discriminates” against an employee in violation of section 56.20, subdivision (b), if it improperly retaliates against or penalizes an employee for refusing to authorize the employee’s health care provider to disclose confidential medical information to the employer or others (see Civ. Code, §56.11), or for refusing to authorize the employer to disclose confidential medical information relating to the employee to a third party (see Civ. Code, § 56.21). By contrast, an employer who disqualifies an employee or job applicant for refusing to permit the employer to be informed of the ultimate results of an employer-mandated medical examination or drug test, like an employer who disqualifies an employee or applicant who fails or refuses to take the required examination or test, has not “discriminated” against the employee or applicant for refusing to sign an authorization of disclosure, but instead simply has taken “such action as is necessary in the absence of medical information due to [the] employee’s refusal. . . ,” as specifically authorized by section 56.20, subdivision (b). This follows because an employer-mandated medical examination or drug testing procedure obviously would be totally ineffective if an employer could not treat an individual who refuses to permit the employer to learn the ultimate results of the examination in the same fashion as an individual who refuses to complete the test. Although plaintiff maintains that the language in Civil Code section 56.20, subdivision (b), permitting an employer to take “such action as is necessary in the absence of medical information due to an employee’s refusal to sign an authorization” (italics added) should be interpreted to require an employer to justify any employer-mandated medical examination or drug test under a demanding “compelling interest” standard, plaintiff has not cited, and our independent research has not identified, anything in either the language or legislative history of section 56.20, subdivision (b), that indicates the Legislature, in enacting this provision, intended to impose any such stringent requirement on employer-mandated medical examinations or drug testing. Indeed, although section 56.20, subdivisions (a) and (c) (quoted in fn. 5, ante), reasonably can be interpreted as imposing restrictions upon an employer’s handling and disclosure of information about an applicant obtained through an employer-mandated medical examination or drug test, there is nothing in the language or legislative history of the Confidentiality of Medical Information Act to suggest that the Legislature, in drafting this enactment, ever considered the entirely distinct question of whether, and under what circumstances, an employer may require a job applicant or current employee to submit to an employer-administered medical examination or drug test as a condition of employment. In the absence of any indication that the Legislature, in enacting this legislation, intended to address the validity of employer-mandated medical examinations or drug tests, we do not believe that section 56.20, subdivision (b), can or should be interpreted as having resolved this significant issue by implication. Accordingly, we conclude that so long as an employer-mandated medical examination or drug testing program is otherwise lawful, section 56.20, subdivision (b), does not prohibit an employer from disqualifying an applicant or employee who refuses to authorize disclosure to the employer of the ultimate results of the examination or test. Our conclusion that Civil Code section 56.20, subdivision (b), cannot reasonably be interpreted to regulate the circumstances under which an employer may require job applicants or current employees to submit to a medical examination or drug test is bolstered by the circumstance that, in contrast to the Confidentiality of Medical Information Act, other statutory provisions exist, both at the federal and state level, that speak directly to the question of the validity of employer-mandated medical examinations and drug testing. At the federal level, the most pertinent statute is the Americans with Disabilities Act (42 U.S.C. § 12101 et seq.) (ADA), enacted in 1990. The ADA contains a number of explicit provisions related to employer-required medical examinations, establishing different rules applicable to various stages of the application and employment process. In the initial stage of the application process, prior to the time an employer has made an offer of employment to a job applicant, the ADA prohibits any employer covered by the act from conducting a medical examination of any applicant. (42 U.S.C. § 12112(d)(2)(A).) After an employer has made an offer of employment to a job applicant and before the applicant begins his or her employment duties, however, the ADA specifically provides that an employer may require a job applicant to undergo a medical examination, and may condition its offer of employment on the results of such examination, so long as (1) all entering employees are subjected to such an examination regardless of disability, (2) information obtained through the examination regarding the medical condition or history of the applicant is collected and maintained in separate medical files and is treated as a confidential medical record, and (3) the results of the examination are used only in accordance with the other provisions of the ADA (i.e., the results may not be used to discriminate against a qualified individual with a disability). (42 U.S.C. § 12112(d)(3).) The administrative regulation implementing this section of the act further explains that, at this stage, “[mjedical examinations conducted in accordance with this section do not have to be job-related and consistent with business necessity.” (29 C.F.R. § 1630.14(b)(3) (1996).) Finally, after an employee has been hired and has begun working, the ADA provides that an employer “shall not require a medical examination . . . unless such examination . . . is shown to be job-related and consistent with business necessity.” (42 U.S.C. § 12112(d)(4)(A).) Thus, the ADA establishes a rather detailed scheme regulating employer-required medical examinations, prohibiting such examinations at some stages of the application and employment process, but specifically permitting an employer, at the post-offer/pre-hiring stage, to require such medical examinations of all applicants without any showing that the examination “is . . . job-related and consistent with business necessity.” (42 U.S.C. § 12112(d)(4)(A).) Furthermore, although the ADA places some significant limitations upon the circumstances under which an employer may require current employees or applicants for employment to undergo medical examinations, the act contains a specific provision declaring that “[f]or purposes of this subchapter, a test to determine the illegal use of drugs shall not be considered a medical examination” (42 U.S.C. § 12114(d)). The legislative history of the ADA and the administrative regulations promulgated pursuant to the act also make clear that the ADA was not intended to restrict an employer’s use of drug testing to determine whether an applicant for employment or a current employee is currently engaging in the illegal use of drugs. At the state level, the question of employer-required medical examinations is addressed explicitly in an administrative regulation that was adopted to implement a provision of the Fair Employment and Housing Act (FEHA), prohibiting discrimination in employment on the basis of physical or mental disability. (See Gov. Code, §§ 12935, subd. (a), 12940.) Under the regulation, an employer may condition an offer of employment upon the results of a medical examination conducted before the employee begins work so long as (1) all entering employees in similar positions are subjected to such an examination, (2) the applicant or employee is permitted to “submit independent medical opinions for consideration” before the applicant is disqualified based upon the results of the examination, and (3) the results of the examination are maintained on separate forms and are treated as confidential medical records. (Cal. Code Regs., tit. 2, § 7294.0, subd. (d).) Moreover, like the ADA, the FEHA specifically provides that “the unlawful use of controlled substances or other drugs shall not be deemed, in and of itself, to constitute a mental [or physical] disability” for purposes of the provisions of the act prohibiting discrimination on the basis of mental or physical disability (Gov. Code, § 12926, subds. (i), (k)), and nothing in the FEHA, or any other California statute, purports to prohibit, or place general limitations upon, employer-mandated drug Of course, the Legislature remains free to impose greater restrictions upon employer-mandated medical examinations or drug testing than those embodied in the current provisions of the ADA or the FEHA. Contrary to plaintiff’s contention, however, we believe it is clear that the Legislature did not intend to impose such restrictions when it enacted the applicable provisions of the Confidentiality of Medical Information Act in 1981. Accordingly, we reject plaintiff’s contention that the city’s drug testing program—by disqualifying applicants who refuse to authorize the release of drug test results to the city—improperly “discriminates” against such applicants in violation of Civil Code section 56.20, subdivision (b). Having found that plaintiff’s sole statutory challenge to the city’s drug testing program is without merit, we turn to plaintiff’s constitutional contentions. III Plaintiff maintains that the city’s drug testing program violates the provisions of both the United States and California Constitutions. Because the United States Supreme Court already has spoken directly to the issue of the proper application of federal constitutional principles in evaluating the validity of drug testing in the public employment context, whereas our court has not previously had occasion to address the issue of employment-related drug testing under the state Constitution, we believe it is advisable and appropriate to consider plaintiff’s federal constitutional claim before addressing her contention under the state Constitution. The United States Supreme Court addressed the validity of employer-required drug testing in two cases decided in 1989: Skinner v. Railway Labor Executives’ Assn. (1989) 489 U.S. 602 [103 L.Ed.2d 639, 109 S.Ct. 1402] (Skinner) and Treasury Employees v. Von Raab (1989) 489 U.S. 656 [103 L.Ed.2d 685, 109 S.Ct. 1384] (Von Raab). In view of the significance of the Skinner and Von Raab cases, we review these decisions in some detail. A In Skinner, supra, 489 U.S. 602, the court examined the validity, under the Fourth Amendment, of drug testing conducted by a private railroad pursuant to regulations promulgated by the Federal Railroad Administration (FRA). The regulations, imposed because the FRA had found that alcohol and drug abuse by railroad employees poses a serious threat to safety, required the railroad to administer blood and urine tests to employees who were working on trains that were involved in certain relatively serious accidents. The regulations required the railroad, immediately after the occurrence of such an accident, to transport all crew members or other covered employees directly involved in the accident to an independent medical facility, where both blood and urine samples were to be obtained from each employee. (Although primary reliance was placed upon blood samples, urine samples also were required, because drug traces remain in a person’s urine longer than in the blood, and in some cases it would not be possible to transport a worker to a medical facility before certain drugs might be eliminated from the worker’s bloodstream.) In analyzing the validity of the mandated blood and urine tests, the court in Skinner first determined that, because the railroad carried out the testing under the aegis of the federal regulations, there was sufficient governmental “encouragement, endorsement, and participation ... to implicate the Fourth Amendment.” (489 U.S. at pp. 615-616 [103 L.Ed.2d at pp. 658-659].) The court in Skinner thereafter considered whether the blood and urine tests called for by the regulation constituted “searches or seizures” for purposes of the Fourth Amendment. The court first noted that it had “long recognized that a ‘compelled intrusio[n] into the body for blood to be analyzed for alcohol content’ must be deemed a Fourth Amendment search,” explaining that both the physical intrusion, penetrating the skin, and the “ensuing chemical analysis of the sample” constitute invasions of the tested individual’s privacy interests. (489 U.S. at p. 616 [103 L.Ed.2d at p. 659].) Turning to urine testing, and observing that, unlike blood testing, “the procedures ... for collecting and testing urine samples do not entail a surgical intrusion into the body,” the court nonetheless concluded that the administration of a urine test also constitutes a search for purposes of the Fourth Amendment. (Id. at p. 617.) The court explained: “It is not disputed . . . that chemical analysis of urine, like that of blood, can reveal a host of private medical facts about an employee, including whether he or she is epileptic, pregnant, or diabetic. Nor can it be disputed that the process of collecting the sample to be tested, which may in some cases involve visual or aural monitoring of the act of urination, itself implicates privacy interests. . . . ‘There are few activities in our society more personal or private than the passing of urine. Most people describe it by euphemisms if they talk about it at all. It is a function traditionally performed without public observation; indeed, its performance in public is generally prohibited by law as well as social custom.’ [Citation.] Because it is clear that the collection and testing of urine intrudes upon expectations of privacy that society has long recognized as reasonable, the Federal Courts of Appeal have concluded unanimously, and we agree, that these intrusions must be deemed searches under the Fourth Amendment.'” (489 U.S. at p. 617 [103 L.Ed.2d at pp. 659-660], italics added.) Having found that the Fourth Amendment applied to the challenged blood and urine testing, the court in Skinner, emphasizing that this constitutional provision does not proscribe all searches and seizures but only those that are “unreasonable,” proceeded to determine whether the searches mandated by the regulation were reasonable for purposes of the Fourth Amendment. The court observed: “What is reasonable, of course, ‘depends on all of the circumstances surrounding the search or seizure and the nature of the search or seizure itself’ [Citation.] . . . [T]he permissibility of a particular practice ‘is judged by balancing its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate governmental interests.’ [Citations.]” (489 U.S. at p. 619 [103 L.Ed.2d at p. 661], italics added.) Although acknowledging that in most criminal cases this balance is struck in favor of the procedure described by the warrant clause (viewing a search as reasonable if conducted pursuant to a warrant that has been issued by a neutral magistrate upon a showing of probable cause), the court in Skinner noted that past Supreme Court decisions had recognized exceptions to this rule “ ‘when “special needs, beyond the normal need for law enforcement, make the warrant and probable-cause requirement impracticable.” ’ [Citations.] When faced with such special needs, we have not hesitated to balance the governmental and privacy interests to assess the practicality of the warrant and probable-cause requirements in the particular context. [Citations.]” (Id. at pp. 619-624 [103 L.Ed.2d at p. 661].) Examining the specific context presented in Skinner, the court found that “[t]he Government’s interest in regulating the conduct of railroad employees to ensure safety, like its supervision of probationers or regulated industries, or its operation of a government office, school, or prison, ‘likewise presents “special needs” beyond normal law enforcement that may justify departures from the usual warrant and probable-cause requirements.’ ” (489 U.S. at p. 620[ 103 L.Ed.2d at pp. 661-662].) After concluding that imposition of a warrant requirement in this context “would add little to the assurances of certainty and regularity already afforded by the regulations, while significantly hindering, and in many cases frustrating, the objectives of the Government’s testing program” (id. at p. 624 [103 L.Ed.2d at p. 664]), the court turned to the more difficult question whether the testing program was impermissible because it subjected employees to blood and urine testing in the absence not only of a showing of probable cause to believe that an employee had used illicit drugs or alcohol, but also in the absence of a showing of even an individualized suspicion of recent drug or alcohol use. Although the court in Skinner noted that “[w]hen the balance of interests precludes insistence on a showing of probable cause, we have usually required ‘some quantum of individualized suspicion’ before concluding that a search is reasonable [citation],” (ibid.) it further explained that past cases also had indicated “that a showing of individualized suspicion is not a constitutional floor, below which a search must be presumed unreasonable,” and that “[/]« limited circumstances, where the privacy interests implicated by the search are minimal, and where an important governmental interest furthered by the intrusion would be placed in jeopardy by a requirement of individualized suspicion, a search may be reasonable despite the absence of such suspicion.” (Ibid., italics added.) The court then went on to conclude that, under the circumstances presented in Skinner, the governmental interest in testing without a showing of individualized suspicion outweighed the intrusion on privacy posed by the tests for illegal drugs and alcohol. In reaching this conclusion, the court emphasized the compelling nature of the governmental interest supporting the testing at issue in Skinner, explaining that the railroad “[e]mployees subject to the tests discharge duties fraught with such risks of injury to others that even a momentary lapse of attention can have disastrous consequences” (489 U.S. at p. 628 [103 L.Ed.2d at p. 667]), and that “[m]uch like persons who have routine access to dangerous nuclear power facilities, [citations], employees who are subject to testing under the FRA regulations can cause great human loss before any signs of impairment become noticeable to supervisors or others. [H ... [H ... By ensuring that employees in safety-sensitive positions know they will be tested upon the occurrence of a triggering event, the timing of which no employee can predict with certainty, the regulations significantly increase the deterrent effect of the administrative penalties associated with the prohibited conduct, [citation], concomitantly increasing the likelihood that employees will forgo using drugs or alcohol while subject to being called for duty.” (Id. at pp. 628-630 [103 L.Ed.2d at pp. 667-668].) The court in Skinner also found that several circumstances operated to diminish the intrusion upon reasonable expectations of privacy resulting from the challenged testing program. Although the court stated that “in most contexts” it would not characterize as minimal the privacy concerns implicated by urine testing, “which require[s] employees to perform an excretory function traditionally shielded by great privacy” (489 U.S. at p. 626 [103 L.Ed.2d at p. 665]), the court noted that the regulations at issue in Skinner attempted to reduce the intrusiveness of the collection process by not requiring that samples be furnished under the direct observation of a monitor, and by providing that the sample was to be collected “in a medical environment, by personnel unrelated to the railroad employer, . . . not unlike similar procedures encountered often in the context of a regular physical examination.” (Id. at pp. 626-627 [103 L.Ed.2d at pp. 665-666].) Further, the court stated that “[m]ore importantly, the expectations of privacy of covered employees are diminished by reason of their participation in an industry that is regulated pervasively to ensure safety, a goal dependent, in substantial part, on the health and fitness of covered employees.” (Id. at p. 627 [103 L.Ed.2d at p. 666].) The court noted that both federal and state legislation contemplated that railroad workers would be subjected to thorough examination for safety purposes, and that the FRA had found that “ ‘most railroads require periodic physical examinations for train and engine employees and certain other employees’ [citation].” (Ibid.) The court concluded that “[flhough some of the privacy interests implicated by the toxicological testing at issue reasonably might be viewed as significant in other contexts, logic and history show that a diminished expectation of privacy attaches to information relating to the physical condition of covered employees and to this reasonable means of procuring such information.” (Id. at p. 628 [103 L.Ed.2d at p. 667].) In light of the compelling governmental interests that it found would be significantly hindered if railroads were required to point to specific facts giving rise to a reasonable suspicion of impairment before testing an employee, and its conclusion that the testing authorized by the regulations was not an undue infringement on the justifiable expectations of privacy of covered employees, the court in Skinner held that “the Government’s compelling interests outweigh privacy concerns” (489 U.S. at p. 633 [103 L.Ed.2d at p. 670]) and accordingly concluded that the alcohol and drug tests in question were “reasonable within the meaning of the Fourth Amendment.” (Id. at p. 634 [103 L.Ed.2d at p. 671].) Thus, the court rejected the challenge to the drug and alcohol testing program at issue in Skinner. B Although Skinner provides considerable guidance with respect to the general application of Fourth Amendment principles to employment-related drug testing, the United States Supreme Court’s decision in Von Raab, supra, 489 U.S. 656, handed down the same day as Skinner, is even more instructive with regard to the validity of the drug testing program at issue in the present case. The drug and alcohol tests involved in Skinner were conducted only after a train accident had occurred, whereas the drug testing in Von Raab, like the testing here at issue, was imposed upon employees upon their application for transfer or promotion to new positions. In Von Raab, the court considered a challenge to a drug testing program that had been adopted by the United States Customs Service. Under that agency’s program, “[d]rug tests were made a condition of placement or employment for positions that meet one or more of three criteria. The first is direct involvement in drug interdiction or enforcement of related laws, an activity the Commissioner [of Customs] deemed fraught with obvious dangers to the mission of the agency and the lives of Customs agents. [Citation.] The second criterion is a requirement that the incumbent carry firearms, as the Commissioner concluded that ‘[p]ublic safety demands that employees who carry deadly arms and are prepared to make instant life or death decisions be drug free.’ [Citation.] The third criterion is a requirement for the incumbent to handle ‘classified’ material, which the Commissioner determined might fall into the hands of smugglers if accessible to employees who, by reason of their own illegal drug use, are susceptible to bribery or blackmail.” (489 U.S. at pp. 660-661 [103 L.Ed.2d at p. 699].) Under the customs program, once an employee qualifies for a position covered by the testing program, the Customs Service notifies the employee that final selection is contingent upon successful completion of drug screening. The employee is directed to report to a testing facility at a particular date and time. At the testing site, the employee is required to remove outer garments (such as a coat or jacket) and any other personal belongings, and is permitted to produce the sample either behind a partition or in a bathroom stall. “To ensure against adulteration of the specimen, or substitution of a sample from another person, a monitor of the same sex as the employee remains close at hand to listen for the normal sounds of urination. Dye is added to the toilet water to prevent the employee from using the water to adulterate the sample.” (489 U.S. at p. 661 [103 L.Ed.2d at p. 699].) The monitor inspects the sample for temperature and color and places it in a tamper-proof container, which is sealed. Chain-of-custody procedures are utilized to protect the integrity of the process. Under the Customs Service program, current employees who test positive for drugs, and offer no satisfactory explanation, are subject to dismissal from the Customs Service. In analyzing the validity of the Customs Service program as applied to current employees who had been offered transfer or promotion, the court in Von Raab began by explaining that “earlier cases have settled that the Fourth Amendment protects individuals from unreasonable searches conducted by the Government, even when the Government acts as an employer [citing O’Connor v. Ortega (1987) 480 U.S. 709 [94 L.Ed.2d 714, 107 S.Ct. 1492], and, in view of our holding in [Skinner] that urine tests are searches, it follows that the Customs Service’s drug-testing program must meet the reasonableness requirement of the Fourth Amendment.” (Von Raab, supra, 489 U.S. at p. 665 [103 L.Ed.2d at pp. 701-702].) As in Skinner, the court also noted that although, as a general matter, a search must be supported by a warrant issued upon probable cause, “where a Fourth Amendment intrusion serves special governmental needs, beyond the normal need for law enforcement, it is necessary to balance the individual’s privacy expectations against the Government’s interests to determine whether it is impractical to require a warrant or some level of individualized suspicion in the particular context.” (489 U.S. at pp. 665-666 [103 L.Ed.2d at p. 702].) Observing that the Customs Service drug testing program was not designed to serve the ordinary needs of law enforcement (test results could not be used in a criminal prosecution without the employee’s consent), the court in Von Raab found that the purposes of the program—“to deter drug use among those eligible for promotion to sensitive positions within the Service and to prevent the promotion of drug users to those positions” (id. at p. 666 [103 L.Ed.2d at p. 702])—like the government’s concern for safe rail transportation in Skinner, embodied a “special need” that could justify departure from the ordinary warrant and probable cause requirements. The court explained that a warrant is not required in this context, because under the Customs Service program every employee who sought transfer or promotion to a covered position was tested, and in light of the circumstance that “the Service does not make a discretionary determination to search based on a judgment that certain conditions are present, there are simply ‘no special facts for a neutral magistrate to evaluate’ [citation].” (Von Raab, supra, 489 U.S. at p. 667 [103 L.Ed.2d at p. 703].) The court then went on to examine the more difficult question whether the drug testing could be justified in the absence of any individualized suspicion of illicit drug use by the employees who were subject to testing. Reiterating that “[o]ur precedents have settled that, in certain limited circumstances, the Government’s need to discover . . . latent or hidden conditions, or to prevent their development, is sufficiently compelling to justify the intrusion on privacy entailed by conducting such searches without any measure of individualized suspicion,” the court found that “the Government’s need to conduct the suspicionless searches required by the Customs program outweighs the privacy interests of employees engaged directly in drug interdiction, and of those who otherwise are required to carry firearms.” (489 U.S. at p. 668 [103 L.Ed.2d at p. 704], italics added.) In explaining this conclusion, the court emphasized both the significance of the government’s interest with regard to these particular employment positions, and the diminished expectation of privacy of the individuals seeking such positions. With regard to drug-interdiction personnel, the court stated; “It is readily apparent that the Government has a compelling interest in ensuring that front-line interdiction personnel are physically fit, and have unimpeachable integrity and judgment. . . . This national interest in self-protection could be irreparably damaged if those charged with safeguarding it were, because of their own drug use, unsympathetic to their mission of interdicting narcotics. A drug user’s indifference to the Service’s basic mission or, even worse, his active complicity with the malefactors, can facilitate importation of sizable drug shipments or block apprehension of dangerous criminals.” (Von Raab, supra, 489 U.S. at p. 670 [103 L.Ed.2d at p. 705].) With respect to employment positions that require the carrying of a firearm, the court declared: “Customs employees who may use deadly force plainly ‘discharge duties fraught with such risks of injury to others that even a momentary lapse of attention can have disastrous consequences.’ [Citation.] We agree with the Government that the public should not bear the risk that employees who may suffer from impaired perception and judgment will be promoted to positions where they may need to employ deadly force.” (Id. at pp. 670-671 [103 L.Ed.2d at p. 705].) Having highlighted the important public interests supporting suspicionless testing of those Customs Service positions involving drug interdiction and requiring the carrying of a firearm, the court examined the intrusion upon privacy resulting from compelling employees seeking transfer or promotion to such positions to undergo the challenged urine test for drugs. The court first noted that it had recognized in Skinner that “[t]he interference with individual privacy that results from the collection of a urine sample for subsequent chemical analysis could be substantial in some circumstances.” (Von Raab, supra, 489 U.S. at p. 671 [103 L.Ed.2d at p. 705].) It then went on: “We have recognized, however, that the ‘operational realities of the workplace’ may render entirely reasonable certain work-related intrusions by supervisors and co-workers that might be viewed as unreasonable in other contexts. [Citation.] While these operational realities will rarely affect an employee’s expectations of privacy with respect to searches of his person, or of personal effects that the employee may bring to the workplace [citation], it is plain that certain forms of public employment may diminish privacy expectations even with respect to such personal searches. Employees of the United States Mint, for example, should expect to be subject to certain routine personal searches when they leave the workplace every day. Similarly, those who join our military or intelligence services may not only be required to give what in other contexts might be viewed as extraordinary assurances of trustworthiness and probity, but also may expect intrusive inquiries into their physical fitness for those special positions. [Citations.]” (Id. at pp. 671-672 [103 L.Ed.2d at p. 706].) Turning to the two categories of Customs Service employees it then was considering, the court continued: “We think Customs employees who are directly involved in the interdiction of illegal drugs or who are required to carry firearms in the line of duty likewise have a diminished expectation of privacy in respect to the intrusions occasioned by a urine test. Unlike most private citizens or government employees in general, employees involved in drug interdiction reasonably should expect effective inquiry into their fitness and probity. Much the same is true of employees who are required to carry firearms. Because successful performance of their duties depends uniquely on their judgment and dexterity, these employees cannot reasonably expect to keep from the Service personal information that bears directly on their fitness. [Citation.] While reasonable tests designed to elicit this information doubtless infringe some privacy expectations, we do not believe these expectations outweigh the Government’s compelling interests in safety and in the integrity of our borders.” (Von Raab, supra, 489 U.S. at p. 672 [103 L.Ed.2d at p. 706], fn. omitted.) After concluding that the Government’s “interests in safeguarding [the nation’s] borders and the public safety outweigh the privacy expectations of employees who seek to be promoted to positions that directly involve the interdiction of illegal drugs or that require the incumbent to carry a firearm,” and thus that “the testing of these employees is reasonable under the Fourth Amendment” (Von Raab, supra, 489 U.S. at p. 677 [103 L.Ed.2d at p. 709]), the court went on to consider whether such tests also were constitutionally reasonable with regard to the third category of employees to whom the drug testing program applied, employees who were required to handle classified material. The court indicated it agreed “that the Government has a compelling interest in protecting truly sensitive information from those who . . . ‘. . . might compromise [such] information’ [citations],” and that “employees who seek promotions to positions where they would handle sensitive information can be required to submit to a urine test under the Service’s screening program, especially if the positions covered under this category require background investigations, medical examinations, or other intrusions that may be expected to diminish their expectations of privacy in respect of a urinalysis test.” (489 U.S. at p. 677 [103 L.Ed.2d at pp. 709-710].) The court, however, expressed concern whether this category of employees in fact “encompasses only those Customs employees likely to gain access to sensitive information,” suggesting that the record indicated that the category included “those holding such diverse positions as ‘Accountant,’ ‘Accounting Technician,’ ‘Animal Caretaker,’ ‘Attorney (All),’ ‘Baggage Clerk,’ ‘Co-op Student (All),’ ‘Electric Equipment Repairer,’ ‘Mail Clerk/Assistant,’ and ‘Messenger.’ ” (Id. at p. 678 [103 L.Ed.2d at p. 710].) Because it was not evident to the court that all of the employees holding such positions were likely to gain access to sensitive information, the court concluded it was appropriate to remand the matter “for such proceedings as may be necessary to clarify the scope of this category of employees subject to testing.” (Ibid.) The lower court thus was directed, on remand, to “examine the criteria used by the Service in determining what materials are classified and in deciding whom to test under this rubric,” and also to consider, “[i]n assessing the reasonableness of requiring tests of these employees,” “pertinent information bearing upon the employees’ privacy expectations, as well as the supervision to which these employees are already subject.” (Ibid..) The court in Von Raab summarized its holding as follows: “We hold that the suspicionless testing of employees who apply for promotion to positions directly involving the interdiction of illegal drugs, or to positions that require the incumbent to carry a firearm, is reasonable. The Government’s compelling interests in preventing the promotion of drug users to positions where they might endanger the integrity of our Nation’s borders or the life of the citizenry outweigh the privacy interests of those who seek promotion to these positions, who enjoy a diminished expectation of privacy by virtue of the special, and obvious, physical and ethical demands of those positions. We do not decide whether testing those who apply for promotion to positions where they would handle ‘classified’ information is reasonable because we find the record inadequate for this purpose.” (489 U.S. at p. 679 [103 L.Ed.2d at pp. 710-711].) C In addition to the decisions in Skinner and Von Raab, the United States Supreme Court more recently decided another drug testing case—Vernonia School Dist. 47J v. Acton (1995) 515 U.S. 646 [132 L.Ed.2d 564, 115 S.Ct. 2386] (Vernonia)—that sheds some light on the proper application of the Fourth Amendment to the drug testing program here at issue. In Vernonia, the court co