OVERVIEW
D.W. NELSON, Circuit Judge:Petitioner Local 1245 of the International Brotherhood of Electrical Workers (“Local 1245”) appeals the Nuclear Regulatory Commission’s (“NRC”) refusal to exempt clerical, warehouse, and maintenance employees at the Diablo Canyon nuclear power plant from an industry-wide drug testing program. Local 1245 argues that the testing program is unconstitutional as applied to these employees because they do not have access to the “vital areas” of the plant, are highly supervised, and do not perform job duties that could compromise plant safety. We affirm the decision of the NRC. Local 1245 has failed to establish that the groups of workers in question are not in safety-sensitive positions.
FACTUAL AND PROCEDURAL BACKGROUND
On June 7, 1989, the NRC promulgated “fitness-for-duty” regulations that required all commercial nuclear power plants to develop and implement fitness for duty (“FFD”) programs.1 The regulations specified that each FFD program must include a random drug testing program for workers who have unescorted access to “protected areas” of nuclear facilities.2 10 C.F.R. § 26.24 (1990). In accordance with the regulations, the Pacific Gas and Electric Company, which owns and operates the Diablo Canyon nuclear power plant, adopted a new FFD. program requiring random urine testing for Diablo Canyon employees to take effect beginning January 3, 1990.
Diablo Canyon is located at the end of an eight-mile road that is guarded twenty-four hours a day. The plant's facilities are divided into three areas with increasingly restricted access. The unprotected area contains the parking lots, a training building, construction and engineering offices, and secondary warehouses. The protected area of the plant contains the administrative building, the turbine building, and various warehouse, security, and fuel handling buildings.3 Access to this area is restricted to individuals who have been granted “unescorted access” and employees must also pass through a series of control checkpoints before entering. Finally, the vital areas of the plant contain the auxiliary and containment buildings, which house the reactor, cooling pumps, generators, and other safety-sensitive equipment. Access to these areas is restricted to specified employees who are given special computer key cards. However, there are no guards at the entrances to vital areas, so an employee without a key card could theoretically follow another employee into the vital areas.
Local 1245 represents approximately 90 clerical employees at Diablo Canyon, with *524job titles ranging from “Routine Plant Clerk” to “Clerical Assistant.” Both parties agree that the vast majority of these employees work only in the administrative building within the protected area, but that some clerical employees require access to vital areas of the plant.4 Although clerical employees perform mainly secretarial and administrative duties, the NRC alleges that some of these employees process access and security clearances and would be required to staff the plant’s emergency response center in the event of a nuclear emergency.
Local 1245 also represents approximately 50 warehouse employees who perform traditional warehouse functions such as receiving, storing, categorizing, and disbursing. Local 1245 contends that their work is not safety-related, in part because any safety-sensitive materials received at the warehouse are also checked by the plant’s quality control department. The NRC responds that their work is safety-sensitive because any error in the cataloging or disbursing process could result in the wrong material being installed in a plant system. Although they disagree as to the frequency, both parties agree that warehousemen at least occasionally have to enter vital areas of the plant to deliver materials and equipment.
Between 250 and 300 maintenance workers are also members of Local 1245. These employees maintain and repair the mechanical and electric equipment of the plant. Local 1245 concedes that this work is considered safety-sensitive and of necessity is often performed within the vital areas of the plant.
On March 13, 1990, Local 1245 filed a letter with the NRC requesting that its members be exempted from Diablo Canyon’s random drug testing program.5 The NRC responded that it considered Local 1245’s request to be both a petition for an exemption and a request that the NRC reconsider or amend its FFD rule. Accordingly, the NRC also referred Local 1245’s petition to staff as a petition for rulemak-ing and told Local 1245 that it needed to file specific proposed amendments to the rule. Local 1245 chose not to pursue this course of action and accordingly never perfected a petition for rulemaking.
In regard to the petition for an exemption, both Local 1245 and Pacific Gas & Electric filed supplemental information pursuant to the NRC’s request. On September 24, 1990, and without a hearing, the NRC denied Local 1245’s request for an exemption, chiefly on the grounds that Local 1245 had not established that its employees differed in any significant way from similar employees at other power plants and that Local 1245 had not advanced any arguments different from those considered and rejected by the NRC at the time it promulgated the rule. The NRC also noted that all workers with access to protected areas of the plant had the potential both to distribute illegal substances to other plant employees and to threaten the safety of the plant. This appeal followed.6
STANDARD OF REVIEW
We must uphold the NRC decision denying the exemption unless it was “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A). The scope of review under the arbitrary and capricious standard is narrow and we may not substitute our judgment for that of the agency. Motor Vehicle Manufacturing Ass’n v. State Farm Mutual Auto Ins. Co., 463 U.S. 29, *52543, 103 S.Ct. 2856, 2866, 77 L.Ed.2d 443 (1983).
DISCUSSION
In the past few years, many of the threshold questions regarding the constitutionality of drug testing have been settled.7 First, “drug testing performed by private employers under compulsion of government regulation constitutes governmental action subject to constitutional restrictions.” Bluestein v. Skinner, 908 F.2d 451, 455 (9th Cir.1990), cert. denied, - U.S. -, 111 S.Ct. 954, 112 L.Ed.2d 1042 (1991). Second, urinalysis constitutes a search subject to the restrictions of the Fourth Amendment. National Treasury Employees Union v. Von Raab, 489 U.S. 656, 665, 109 S.Ct. 1384, 1390, 103 L.Ed.2d 685 (1989); Skinner v. Railway Labor Executives, 489 U.S. 602, 616-18, 109 S.Ct. 1402, 1412-13, 103 L.Ed.2d 639 (1989). Third, “the usual Fourth Amendment requirements of a warrant and probable cause do not necessarily apply in the drug testing context.” Bluestein, 908 F.2d at 455. Rather, when a search “serves special governmental needs, beyond the need for normal 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.” Von Raab, 489 U.S. at 665-66, 109 S.Ct. at 1390.
Accordingly, we must balance the privacy interests of Local 1245’s members against the government’s interests to determine whether the application of the NRC’s drug testing program to these employees is constitutional. In evaluating the privacy interests of Local 1245’s employees, “[t]wo considerations guide our analysis: (1) whether as a result of other circumstances employees in this industry already have a diminished expectation of privacy; and (2) whether the particular testing program minimizes the intrusion of privacy.” IBEW, Local 1245 v. Skinner, 913 F.2d 1454, 1463 (9th Cir.1990). Local 1245 concedes that by virtue of their employment in an extensively regulated industry,8 employees of nuclear power plants have a diminished expectation of privacy. See Rushton v. Nebraska Public Power District, 844 F.2d 562, 566 (8th Cir.1988). Moreover, Local 1245 mounts no challenge to the procedures used in conducting the drug tests. The critical question is thus whether the government’s asserted interests rise to a sufficient level to justify random testing of these employees.
The NRC asserted governmental interests in public safety and in the reliability and integrity of its workforce in denying Local 1245’s request for an exemption, but it advances only the public safety rationale before this court.9 As to this rationale, the NRC emphasizes that the nuclear power industry has the potential to inflict catastrophic harm on society. Indeed, courts have repeatedly used the nuclear industry as an example of a workplace that “could produce such catastrophic social harm that *526no risk whatever is tolerable.” Von Raab, 489 U.S. at 684, 109 S.Ct. at 1400 (Scalia, J., dissenting). The NRC also asserts that all persons who have unescorted access to the protected areas of a nuclear power plant have the potential to endanger public safety, even if their own jobs are not safety-related and even if they are not permitted to enter the vital areas.
The NRC advances three arguments in support of this assertion. First, the NRC suggests that workers could smuggle drugs into the facility. We find this theory insufficient to justify testing in the nuclear power industry. Cases that have accepted this rationale have generally involved drug testing of prison guards. See, e.g., Taylor, 888 F.2d at 1197. Although prison guards or even customs officials may have ready access to both a supply of and a demand for drugs, this possibility seems far more remote in a nuclear power plant.
Second, the NRC argues that drug-impaired workers could engage in deliberate or accidental actions that could threaten safety systems. As an actual example, the NRC cites a crane operator at Diablo Canyon who — although he was not under the influence of drugs at the time— knocked over a power line, causing a power outage in one of the plant’s safety systems. Another hypothetical example even more directly germane to this case is that of a drug-impaired worker roaming freely through the plant’s control room, a situation obviously fraught with the danger that the worker will accidentally interfere with a safety system. The NRC’s third argument is the possibility that a drug-impaired worker could interfere with the ability of a worker in a clearly safety-sensitive position to operate and maintain the plant. To return to the control room example, an employee could become distracted from his responsibilities by the pressing need to remove a drug-impaired coworker from the scene. Because of their speculative nature, these latter arguments are not entirely persuasive. We do not deny that the government has a strong interest in random testing of nuclear industry employees who are in safety-sensitive positions. However, the government's blanket inclusion of all workers in protected areas may in some cases be overkill.
If Local 1245 were able to establish that the clerical workers did not engage in any safety-sensitive work and had no access to the plant’s vital areas, the balance of interests might well be different. However, it is apparent that at least some of the clerical employees at Diablo Canyon do enter the vital areas of the plant and may have safety-related responsibilities. Moreover, it appears that this group of clerical workers with access to vital areas is not a static one; the composition of the group could vary because of task assignments or work-shifts. On the record before this court, it is impossible for us to ascertain whether there is some group of clerical workers for whom testing would be inappropriate. We suspect many clerical workers cannot fairly be classified as having safety-sensitive jobs. However, in light of our inability to distinguish between those clerical workers who pose a real threat to public safety and those who do not, we are unwilling to reverse the NRC’s denial of an exemption at this time.10
In the case of the warehouse employees, from the record before us, it appears many are engaged in work that is sufficiently safety-sensitive to warrant upholding the NRC’s denial of an exemption. These employees apparently actually handle safety-sensitive material and often enter the vital areas of the plant to make deliveries. Local 1245 argues that the fact that the work hours of warehouse employ*527ees are not limited is proof that the employees are not engaged in safety-sensitive work. However, we rejected this argument in a drug testing case involving flight attendants. Bluestein, 908 F.2d at 457 (“The duty time decisions, however, do not stand for the proposition that impairment of ... performance is never a public safety consideration.”). Local 1245 has failed to establish a discrete record as to certain warehousemen that would entitle some of them to exemptions.
Finally, we believe that random drug testing of the maintenance employees is clearly constitutional.11 Local 1245 concedes that these workers, who are responsible for repairs on undisputably vital equipment, are indeed engaged in safety-sensitive work. Local 1245 argues instead that Diablo Canyon’s design features, redundancy of safety systems, extensive training procedures, and the doubleehecking of all maintenance work makes the drug testing program unnecessary. However, as we noted in a drug testing case involving pipeline workers, “[t]he heavy supervision of workers ... does not ... negate the need for other mechanisms to prevent accidents.” IBEW, 913 F.2d at 1460 n. 14. The Rushton court rejected this same argument as well, concluding that extra safety measures were not made superfluous simply because the nuclear plant was designed to withstand an impaired operator. Rushton, 844 F.2d at 565. Because maintenance workers are engaged in undeniably safety-sensitive work, the decisión of the NRC regarding them is affirmed.12
CONCLUSION
The decision of the NRC is AFFIRMED.
. The regulations were promulgated after full notice and comment proceedings.
. "Protected areas” are defined as those areas of the plant surrounded by physical barriers and to which access is restricted. 10 C.F.R. § 26.3. The most sensitive areas of a nuclear facility are designated as “vital areas,” which generally contain the reactor and other radiologically sensitive equipment.
. The parties disagree about whether the protected areas of the plant contain equipment that is essential to safe plant operations. Local 1245 states simply that the protected area does not contain any safety-sensitive equipment. The NRC contends, without much more specificity, that the protected area contains equipment that provides additional pertinent information in the event of unusual conditions and provides "additional capacity” to cope with those conditions.
. The NRC alleges that some clerical employees even require access to the plant’s control room in order to perform their duties.
. The NRC's rules permit exemptions which "will not endanger life or property or the common defense or security.” 26 C.F.R. § 26.6.
. On December 29, 1989, several individual Dia-blo Canyon employees filed suit against Pacific Gas & Electric seeking injunctive relief against the random drug testing program. Although a temporary restraining order was initially granted, the district court later determined that it did not have jurisdiction, dissolved the order, and transferred the matter to the Ninth Circuit. The Ninth Circuit denied the plaintiffs’ request for emergency relief and the plaintiffs eventually filed a motion for a voluntary dismissal of the appeal, which was granted on October 9, 1990.
. As a preliminary matter, we note that the NRC initially argued that Local 1245 was not entitled in this proceeding to seek review of the constitutionality of the FFD regulation as applied to its workers. The NRC has since conceded that we can indeed consider Local 1245’s constitutional challenges when reviewing the application of the regulation. See Commonwealth Edison Co. v. NRC, 830 F.2d 610, 614 (7th Cir.1987) ("indirect challenges to the rule brought when the rule is applied to a particular individual are within the court’s jurisdiction.").
. For example, the NRC requires extensive background checks of employees granted unescorted access, access to nuclear power plants is severely limited, and employees are closely observed while inside the plant.
. The NRC wisely decided to refrain from pursuing its integrity of the workforce rationale on appeal. This rationale has almost uniformly been rejected by the courts as insufficient to justify drug testing of employees. See, e.g., Taylor v. O’Grady, 888 F.2d 1189, 1196 (7th Cir. 1989) ("A generalized interest in the integrity of the workforce is, however, not enough to overcome the privacy interests at issue."); Harmon v. Thornburgh, 878 F.2d 484, 490 (D.C.Cir.1989) (noting that integrity of the work force rationale found no support in Von Raab), cert. denied, 493 U.S. 1056, 110 S.Ct. 865, 107 L.Ed.2d 949 (1990).
. The two cases that have considered drug testing in the nuclear power industry — although decided before the Supreme Court’s 1989 decisions — also upheld the programs, emphasizing the vast potential for harm. In Rushton, 844 F.2d at 564, the Eighth Circuit found that drug testing of two engineers was constitutional, even though the men visited the plant for only six to seven hours per month and the chance of their actually causing an accident was small. The Washington Supreme Court upheld drug testing for prospective pipefitters and plumbers at a nuclear power plant. Alverado v. Washington Pub. Power Supply, 111 Wash.2d 424, 759 P.2d 427 (1988), cert. denied, 490 U.S. 1004, 109 S.Ct. 1637, 104 L.Ed.2d 153 (1989).
. The NRC contends that Local 1245 did not request an exemption for maintenance workers before the NRC and accordingly that Local 1245 may not raise this issue on appeal. We reject this argument. Local 1245’s original letter requested an exemption for all Diablo Canyon employees represented by Local 1245, a group which includes maintenance workers. Moreover, in the supplemental materials provided to the NRC, Local 1245 included declarations from maintenance workers and expressly argued in its cover letter that the testing program was unnecessary because extensive protective measures were already in place. Local 1245’s appeal regarding maintenance workers is properly before this court.
. Local 1245 also makes a belated, non-constitutional argument in the conclusion of its brief that the NRC’s decision should be found arbitrary and capricious because it was not based on substantial evidence. This contention is without merit. The NRC explained specifically why it refused to grant the exemption and its decision, especially considering the closeness of the issue as to clerical workers, was a reasonable, if controversial, one. See IBEW, 913 F.2d at 1457; Bluestein, 908 F.2d at 457.