United Steelworkers of America, Afl-Cio-Clc v. Thorne G. Auchter, Assistant Secretary of Labor, Occupational Safety and Health Administration, United States Department of Labor, and the State of New York, the State of New Jersey, the State of Connecticut, and National Paint & Coatings Association, Intervenors. United Steelworkers of America, Afl-Cio-Clc v. Thorne G. Auchter, Assistant Secretary of Labor, Occupational Safety and Health Administration, United States Department of Labor, and the State of New Jersey, Chemical Manufacturers Association, American Petroleum Institute & Atlantic Richfield Company, and National Paint & Coatings Association, Intervenors. Public Citizen, Inc. v. Thorne G. Auchter, Assistant Secretary of Labor, Occupational Safety and Health Administration, United States Department of Labor, and the State of New Jersey, Chemical Manufacturers Association, National Paint & Coatings Association, American Petroleum Institute & Atlantic Richfield Company, Intervenors. Commonwealth of Massachusetts v. Occupational Safety and Health Review Commission, Secretary of Labor, United States Department of Labor, People of the State of Illinois v. United States Department of Labor and John Donovan, Secretary of the United States Department of Labor, the State of New York v. Thorne G. Auchter, Assistant Secretary of Labor, Occupational Safety and Health Administration, United States Department of Labor

Joseph I. Lieberman, Atty. Gen., Richard T. Couture, Asst. Atty. Gen., Hartford, Conn., for the State of Conn.

Timothy J. Waters, Jeanne A. Carpenter, Jeffrey N. Martin, Peabody, Lambert & Meyers, A Professional Corp., Washington, D.C., Bruce Hamill, Gen. Counsel, James Andrew Doyle, National Paint and Coatings Ass'n, Washington, D.C., for Nat. Paint and Coatings Ass'n, Inc.

Richard E. Schwartz, Collier, Shannon, Rill & Scott, Washington, D.C., for the American Iron and Steel Institute as amicus curiae.

Stark Ritchie, Arnold S. Block, Christopher H. Marraro, American Petroleum Institute, Washington, D.C., John P. Meck, Atlantic Richfield Co., Los Angeles, Cal., for American Petroleum Institute, et al.

David C. Vladeck (argued), Alan B. Morrison, Public Citizen Litigation Group, Washington, D.C., for Public Citizen Litigation Group.

Neil F. Hartigan, Atty. Gen., State of Ill., Lee Hettinger, Chief, Stephen Grossmark, Asst. Atty. Gen., Environmental Control Div., Chicago, Ill., for the People of the State of Ill.

Francis X. Bellotti, Atty. Gen., Judith S. Yogman, Asst. Atty. Gen., Stephen S. Ostrach (argued), Asst. Atty. Gen., Government Bureau, Boston, Mass., for petitioner Com. of Mass.

Daniel Marcus (argued), Charles E. Davidow, Wilmer, Cutler & Pickering, Washington, D.C., David F. Zoll, Claire M. Boccella, Chemical Manufacturers Ass'n, Washington, D.C., for Chemical Manufacturers Ass'n.

Beverly Gross, Linda M. Nelson, New York City, for amicus curiae Municipal Labor Committee.

Paul Bardacke, Atty. Gen., Douglas Meiklejohn, Asst. Atty. Gen., Christopher D. Coppin, Asst. Atty. Gen., Santa Fe, N.M., for amicus curiae State of N.M. and the New Mexico Health and Environment Dept.

Peter A. Joy, Cleveland, Ohio, Clifford S. Mitchell, American Medical Student Ass'n, Reston, Va., Peter S. Levine, Nat. Lawyers Guild, Shaker Heights, Ohio, for amicus curiae American Medical Student Ass'n.

Frederick J. Jacobs, New York City, for N.Y. Committee for Occupational Safety and Health.

Bronson C. LaFollette, Atty. Gen., Nadim Sahar, Asst. Atty. Gen., Wis. Dept. of Justice, Madison, Wis., for amicus curiae State of Wis.

Chauncey H. Browning, Atty. Gen., Leonard Knee, Deputy Atty. Gen., Edward Z. Fox, Asst. Atty. Gen., Charleston, W.V., for amicus curiae for the State of W.V.

Before GIBBONS, Circuit Judge, and FISHER, Chief Judge* and KELLY, District Judge**

This case involves consolidated petitions for judicial review of the Hazard Communications Standard promulgated by the Secretary of Labor on the authority of the Occupational Safety and Health Act of 1970 (OSH Act)1, Pub.L. 91-596, 84 Stat. 1590, 29 U.S.C. Sec. 651 et seq. (1982) Certain intervenors challenge our jurisdiction to consider the petitions pursuant to 29 U.S.C. Sec. 655(f) (1982), contending that the action under review is a regulation rather than a standard. Petitioners and the Secretary urge that we have jurisdiction. Petitioners and intervenors challenge the standard on several substantive grounds, while the Secretary defends it. We conclude that the petitions for review are properly here, and thus address the substantive challenges.

Section 6 of the OSH Act directs the Secretary of Labor to promulgate occupational safety and health standards to further the purpose of the Act "to assure so far as possible every working man and woman in the Nation safe and healthful working conditions...." 29 U.S.C. Secs. 651(b) and 655(b)(1) (1982). Any standard promulgated by the Secretary

shall prescribe the use of labels or other appropriate forms of warning as are necessary to insure that employees are apprised of all hazards to which they are exposed, relevant symptoms and appropriate emergency treatment, and proper conditions and precautions of safe use or exposure.

29 U.S.C. Sec. 655(b)(7) (1982).

In 1974, the National Institute for Occupational Safety and Health (NIOSH), an agency created by section 22 of the OSH Act, 29 U.S.C. Sec. 671 (1982), recommended that the Secretary promulgate a standard requiring employers to inform employees of potentially hazardous materials in the workplace. 47 Fed.Reg. 12095 (1982). Later that year the Secretary appointed an advisory committee to develop standards for implementation of the statutory provision requiring labels or other appropriate forms of warning. That advisory committee issued its report on June 6, 1975, recommending a classification of hazards, the use of warning devices such as labels and placards, disclosure of chemical data, and employee training programs. Id. at 12096.

The 1975 Committee report did not result in prompt action by the Secretary. In 1976 a House of Representatives subcommittee held oversight hearings during which several committee members expressed concern over the Secretary's failure to promulgate a comprehensive Hazard Communication Standard. Control of Toxic Substances in the Workplace: Hearings Before the Subcomm. on Manpower and Housing of the House Comm. on Government Operations, 94th Cong. 2d Sess. 87, 89-90 (1976). Seventeen months later, the full House Committee on Government Operations issued a Report which criticized the agency for "miserly use of its delegated powers to deal with disease and death-dealing toxic substances." House Comm. on Government Operations, Failure to Meet Commitments Made in the Occupational Safety and Health Act, H.R.Rep. No. 710, 95th Cong., 1st Sess. 13 (1977). The Committee concluded that:

The Department of Labor should exercise its power under the Occupational Safety and Health Act to insure that employers and workers can and will know what kinds of toxic dangers are present in the Nation's workplaces. OSHA should require chemical formulators to identify any regulated substance in products they sell.

Id. at 15.

Eventually, on January 16, 1981 the agency published a notice of proposed rulemaking entitled "Hazards Identification." 46 Fed.Reg. 4412-53. The standard proposed would be applicable to employers in Division D. Standard Industrial Classification Codes 20-39, which include only employers in the manufacturing sector. Id. at 4426. This classification of employers is made by type of activity for the purpose of promoting uniformity and comparability in the presentation of statistical data. Executive Office of the President, Office of Management and Budget, Standard Industrial Classification Manual 9 (1972). This initial proposal was withdrawn by the Secretary on February 12, 1981 for further consideration of regulatory alternatives. 46 Fed.Reg. 12214. The notice of proposed rulemaking which resulted in the rule challenged in the instant proceedings, entitled "Hazard Communication," was published on March 19, 1982. 47 Fed.Reg. 12091. Like the January 16, 1981 proposal, it was limited to employers in the manufacturing sector. The most significant difference from the rule proposed in 1981 was the inclusion in the March 19, 1982 proposal of a trade secret exception to the requirement that the chemical identities of all hazardous chemicals be disclosed. Compare 46 Fed.Reg. 4426 (1981) with 47 Fed.Reg. 12105 (1982).

The standard was published in its final form on November 25, 1983. 48 Fed.Reg. 53279. It requires that chemical manufacturers and importers "evaluate chemicals produced in their workplaces or imported by them to determine if they are hazardous." 29 C.F.R. Sec. 1910.1200(d)(1) (1984). It refers to several compilations of toxic materials. These lists establish a floor of toxic substances which chemical manufacturers or importers must treat as hazardous. 29 C.F.R. Sec. 1910.1200(d)(3) (1984). Chemicals not included in the designated compilations must be evaluated for hazardousness by reference to "available scientific evidence." 29 C.F.R. Sec. 1910.1200(d)(2) (1984). A manufacturer or importer of chemicals found to be hazardous must "ensure that each container ... leaving the workplace is labeled" with the chemical identity, with appropriate hazard warnings, and with the name and address of the source. 29 C.F.R. Sec. 1910.1200(f)(1) (1984). Manufacturers or importers must also prepare a "material safety data sheet" (MSDS) containing the chemical common names of each hazardous ingredient, and information necessary for safe use of the product. 29 C.F.R. Sec. 1910.1200(g) (1984). The MSDS must be provided to each employer in the manufacturing sector (Standard Industrial Classification Codes 20-39) purchasing a hazardous chemical. That employer must in turn make the MSDS available for employee inspection, 29 C.F.R. Sec. 1910.1200(g)(8) (1984) and "shall provide employees with information and training on hazardous chemicals in their work area...." 29 C.F.R. Sec. 1910.1200(h) (1984).

The rule allows an exception from the labeling and MSDS ingredient disclosure requirements when a chemical manufacturer or importer claims that the chemical identity is a trade secret. 29 C.F.R. Sec. 1910.1200(i) (1984). In such a case, the manufacturer or importer must provide a MSDS disclosing the hazardous properties of the chemical and suggesting appropriate precautions. In the case of a medical emergency, the manufacturer or importer must disclose the chemical identity to a treating physician or nurse, and may later require such a health professional to sign a confidentiality agreement. 29 C.F.R. Sec. 1100.1200(i)(2) (1984). Absent a medical emergency, the manufacturer or importer may be required to disclose the chemical identity to a health professional who makes a written request detailing the occupational need for the information, and who is willing to sign a confidentiality agreement containing a liquidated damages clause. 29 C.F.R. Sec. 1910.1200(i)(3) & (4). In no case is the manufacturer required to disclose the precise formula, as opposed to the identity of chemicals in the compound.

[t]his occupational safety and health standard is intended to address comprehensively the issue of evaluating and communicating chemical hazards to employees in the manufacturing sector, and to preempt any state law pertaining to this subject.

29 C.F.R. Sec. 1910.1200(a)(2) (1984). Thus, at least insofar as they might require hazard communication to employees in the manufacturing sector, state hazard disclosure laws are claimed to be preempted by the rule.

Jurisdiction under Section 6(f) of the OSH Act

Congress has in section 6 of the OSH Act authorized the Secretary to issue health and safety standards. 29 U.S.C. Sec. 655 (1982). In section 8(c)(3) of the Act, Congress also authorized the Secretary to issue regulations requiring employers to keep records and inform employees of worker exposure to potentially toxic materials or harmful physical agents. 29 U.S.C. Sec. 657(c)(3) (1982). Classification of the Hazard Communication Standard as a section 6 standard or a section 8 regulation will have two interrelated consequences.

First, Congress has vested in the courts of appeals jurisdiction over challenges to the validity of section 6 standards. 29 U.S.C. Sec. 655(f) (1982). Congress has made no such decision with respect to judicial review of section 8 regulations. These are reviewable in the district courts pursuant to the Administrative Procedure Act. 5 U.S.C. Sec. 703 (1982). Thus if the Hazard Communication Standard is a section 8 regulation the only course open to us would be to transfer the petitions for review to an appropriate district court. 28 U.S.C. Sec. 1631 (1982). A court of appeals would reach the merits of a dispute over a regulation, therefore, only on an appeal from a judgment of the district court.

Second, by whatever route the case arrived in a court of appeals, whether the challenged rule is a section 6 standard or a section 8 regulation affects its preemptive effect on state law. Section 18(a) of the OSH Act provides explicitly:

Nothing in this chapter shall prevent any State agency or court from asserting jurisdiction under State law over any occupational safety or health issue with respect to which no standard is in effect under section 655 of this title.

29 U.S.C. Sec. 667(a) (1982). If, however, a section 6 standard has been adopted, the role of the states is circumscribed by section 18(b) which provides:

Any State which, at any time, desires to assume responsibility for development and enforcement therein of occupational safety and health standards relating to any occupational safety or health issue with respect to which a Federal standard has been promulgated under section 655 of this title shall submit a State plan for the development of such standards and their enforcement.

29 U.S.C. Sec. 667(b) (1984). The Secretary must accept such a state plan if it "will be at least as effective in providing safe and healthful employment" as the OSHA standards. 29 U.S.C. Sec. 667(c)(2) (1984).

The intervenor states all have hazard disclosure laws which, if not preempted, would be operative in the manufacturing sector. None contend, however, that they have submitted and have obtained approval of their plans pursuant to section 18. Given the explicit language of sections 18(b) and (c), the conclusion is inescapable that if the rule in issue is a section 6 standard it preempts state law until a state obtains section 18 approval of a state plan. It is not likely that the states challenging the rule will seek such approval, for section 18 contemplates that if they do so, they take on the fiscal burdens of enforcement now borne by the United States. 29 U.S.C. Sec. 667(c)(5) (1984).

Since the disclosure requirements of laws adopted by the intervening states are in several respects stricter than those adopted by the Secretary, it is not surprising that those states would have us classify the challenged rule as a section 8 regulation rather than a section 6 standard. The preemptive effect of a section 8 regulation is not dealt with explicitly in the OSH Act, and any implied preemption would require a finding that it is impossible to comply with both federal and state law, or that "the state law stands as an obstacle to the accomplishment of the full purposes and objectives of Congress." Silkwood v. Kerr-McGee Corporation, 464 U.S. 238, 104 S.Ct. 615, 621, 78 L.Ed.2d 443 (1984). It is not likely that we could make either such finding.

The agency decision to include in its rule an express provision preempting state law would, if the rule is a section 8 regulation rather than a standard, be reviewable pursuant to the Administrative Procedure Act. Fidelity Federal Savings and Loan Ass'n v. de la Cuesta, 458 U.S. 141, 102 S.Ct. 3014, 3022, 73 L.Ed.2d 664 (1982). The Secretary's inclusion of an express reference to preemption in the manufacturing sector appears to have been motivated at least in part by the desire to reduce the regulatory burden posed by multiple state laws. 48 Fed.Reg. 53284 (1983). That purpose is arguably at odds with congressional intention that the OSH Act provide a federal floor for safety in the workplace. Reduction of burdens posed by multiple state laws does not appear to have been a significant congressional concern; rather, Congress favored a uniform federal law so that those states providing vigorous protection would not be disadvantaged by those that did not. Subcomm. on Labor of the Sen. Comm. on Labor and Public Welfare, 92d Cong., 1st Sess., Legislative History of the Occupational Safety and Health Act of 1970, Pub.L. No. 91-596 at 144, 413, 444 (1971). We need not, however, decide whether preemption would be implied, or whether the preemption provision of the rule itself is valid as a section 8 regulation, if we conclude that the rule is a section 6 standard, for, as noted above, such standards are explicitly preemptive under the statute.

The Act provides no definition of the term "regulation." The term "occupational safety and health standard" is defined as

a standard which requires conditions, or the adoption or use of one or more practices, means, methods, operations, or processes, reasonably necessary or appropriate to provide safe or healthful employment and places of employment.

29 U.S.C. Sec. 652(8) (1982). This definition is not helpful in the task of differentiating between standards and regulations, for it can hardly be said to exclude the dictionary definition of the term regulation.

The states urge that the difference between section 6 standards and section 8 regulations must be determined by looking at the separate purposes behind the two provisions. Section 6 standards, they urge, serve two purposes: (1) to improve safety in the workplace by removing specific and already-identified hazards; and (2) to provide objective criteria capable of immediate application. Section 8 regulations, they urge, are designed, not for the elimination of specific and already-identified hazards, but for such purposes as the facilitation of investigation and enforcement. The states place principal reliance, in this regard, upon Louisiana Chemical Ass'n v. Bingham, 657 F.2d 777, 782-83 (5th Cir.1981) in which the court classified the agency's Records Access rule as a section 8 regulation. The court in Louisiana Chemical Association held that before proceeding to the merits of a section 6(f) petition for review it must determine "whether the challenged rule reasonably purports to correct a particular 'significant risk' or instead is merely an enforcement or detection procedure designed to further the goals of the Act generally." Id. at 782. It concluded that the Records Access rule was a section 8 regulation.

The quoted distinction provides a convenient test for identifying standards, which this rule satisfies. While both the Records Access rule and the Hazards Communication rule have in common the object of communicating hazard information to employees, the former only provides for access to records maintained by an employer for other purposes, while the latter is aimed at eliminating the specific hazard that employees handling hazardous substances will be more likely to suffer impairment to their health if they are ignorant of the contents of those substances. The Secretary found that inadequate communication is itself a hazard, which the standard can eliminate or mitigate. 48 Fed.Reg. 53321 (1983). See also 48 Fed.Reg. 53282-83, 53323-24, 53327-29 (1983).

The State of New York urges that a communication rule can never be a standard, because it does not provide for diminution of risk through improved protection or reduced exposure. The Secretary found, however, that risk of harm can be greatly reduced by direct warning to employees, who are in the best position to assure that dangerous substances are handled in the safest possible manner. 47 Fed.Reg. 12112. Moreover New York's interpretation of section 6 is inconsistent with the inclusion therein of the direction to the Secretary to promulgate standards which "prescribe the use of labels or other appropriate forms of warning as are necessary to insure that employees are apprised of all hazards to which they are exposed...." 29 U.S.C. Sec. 655(b)(7) (1982). Finally, while we exercise independent judgment as to the distinction between a section 6 standard and a section 8 regulation, the interpretation of those provisions of the OSH Act by the agency charged with its implementation should be afforded some degree of deference. The Secretary has classified the rule as a standard, and urges that the petition for review is properly here.

We conclude, therefore, that the Hazard Communication Standard is a section 6 standard reviewable in this court pursuant to section 6(f).

Preemption of State Hazard Communication Rules in the

Our analysis of the jurisdictional issue disposes of the states' objection to preemption of their hazard disclosure laws with respect to employees in the manufacturing sector. The Hazard Communication Standard, to the extent it is valid, as a section 6 standard, applies to the exclusion of state disclosure laws which have not been approved in accordance with section 18.

Massachusetts, Illinois, New Mexico and West Virginia raise the question whether the federal Hazard Communication Standard operates to preclude state laws outside the manufacturing sector. The Secretary does not contend that the Standard has such an effect. 48 Fed.Reg. 53284; Respondent's Brief at 84-89. He urges, as well, that the issue of the standards's operation outside that sector is not ripe for review. To the extent that the states seek a declaration that their hazard disclosure laws may operate outside the manufacturing sector, we agree that it would be premature to make such a declaration in this case. The Secretary does not urge that they may not so operate, but other parties not before us might present reasons, such as unseverability as a matter of state law, which have not been litigated before this court. We hold only that, to the extent it is valid, the federal Hazard Communication Standard preempts state hazard disclosure laws with respect to disclosure to employees in the manufacturing sector.

Petitioners' challenges to the validity of the standard present three issues: (1) its limited application to the manufacturing sector; (2) the failure to adopt as a list of hazardous substances the Registry of Toxic Effects of Chemical Substances (RTECS) compiled by NIOSH; and (3) the inclusion of the trade secret exemption. We consider the validity of those aspects of the rule under the hybrid review scheme of section 6(f), which refers us to substantial evidence in the rulemaking proceeding. We first interpreted section 6(f) in Synthetic Organic Chemical Manufacturers Association v. Brennan, 503 F.2d 1155 (3d Cir.1974), cert. denied, 420 U.S. 973, 95 S.Ct. 1396, 43 L.Ed.2d 653 (1975). We noted that section 6(e) of the OSH Act requires that whenever the Secretary promulgates a standard he must publish a statement of the reasons for that action in the Federal Register. Id. at 1159-60. We held that these published reasons are subject to judicial review, and that they must be consistent with the language and purpose of the OSH Act. We held, further, that judicial review of a standard involves at least five steps:

(1) determining whether the Secretary's notice of proposed rule making adequately informed interested persons of the action taken;

(2) determining whether the Secretary's promulgation adequately sets forth reasons for his action;

(3) determining whether the statement of reasons reflects consideration of factors relevant under the statute;

(4) determining whether presently available alternatives were at least considered; and

(5) if the Secretary's determination is based in whole or in part on factual matters subject to evidentiary development, whether substantial evidence in the record as a whole supports the determination.

Id. at 1160. This approach to judicial review under section 6(f) has since been consistently followed. See, e.g., American Iron and Steel Institute v. Occupational Safety and Health Administration, 577 F.2d 825, 830-31 (3d Cir.1978), cert. granted, 448 U.S. 909, 100 S.Ct. 3054, 65 L.Ed.2d 1139 (1980), cert. dismissed, 448 U.S. 917, 101 S.Ct. 38, 65 L.Ed.2d 1180 (1980); Atlantic & Gulf Stevedores, Inc. v. Occupational Safety and Health Review Commission, 534 F.2d 541, 551 (3d Cir.1976); AFL-CIO v. Brennan, 530 F.2d 109, 114 (3d Cir.1975). Moreover we have held that "in a Sec. 6(f) proceeding the Secretary has an affirmative burden to demonstrate the reasonableness of an adopted standard." Atlantic & Gulf Stevedores, 534 F.2d at 551.

In this case no petitioner or intervenor questions the adequacy of the Secretary's notice of proposed rulemaking. Our review, therefore, involves the other four Synthetic Organic factors.

B. Limitation of Coverage to the Manufacturing Sector

None of the petitioners still before us contend that the manufacturing sector should not be covered by a hazard communication standard. The Secretary's decision to provide coverage only for employees in the manufacturing sector is based on a finding that this sector, which includes 32% of total employment, accounts for more than 50% of the reported cases of illness due to chemical exposure. 48 Fed.Reg. 53285 (1983). From this datum the Secretary determined that employees in the manufacturing sector have the greatest risk of experiencing health effects due to chemical exposure. Id. Agricultural employees have a higher chemical source incidence rate than manufacturing employees. The Secretary discounted this datum, however, because 80% of the reported chemical source cases among agricultural workers involved skin illnesses from handling plants, which would not be regulated by the proposed Hazard Communication Standard. Id. Moreover the Secretary concluded that the Environmental Protection Administration has, under the Federal Insecticide, Fungicide and Rodenticide Act, exercised jurisdiction over regulation of field use of pesticides. Excluding agricultural employees, there is substantial evidence in the record that the manufacturing sector has the highest incidence rate of chemical exposures which the Agency has authority to regulate.

Several petitioners, while conceding that the finding about incidence rate of illnesses in the manufacturing sector is supported by substantial evidence, contend that the Secretary's exclusion of other sectors such as service, construction, and agriculture, is unsupported by reasons that are consistent with the purposes of the statute. They urge that while the incidence rate for employees in the manufacturing sector is high overall, some employees in specific non-manufacturing categories, such as hospital workers, are exposed to a greater number of toxic substances than are typical workers in the manufacturing sector. Moreover some workers in specific non-covered industries have higher reported rates of chemical source illness and injury than do workers in many covered industries. The Standard Industrial Classification breakdown, they contend, is not relevant to the statute, since that classification is made for a myriad of statistical purposes, mainly economic, having little to do with exposure to hazards. The result of the standard is that spray painters in the manufacturing sector, for example, must be provided with MSDS's and with information and training on hazardous chemicals in the products they use, while spray painters in the construction industry using the same products are not so protected.

In explaining the limited coverage, the Secretary reasoned:

It should be emphasized that the Agency does not believe that employees in other industries are not exposed to hazardous chemicals, or that they should not be informed of those hazards. OSHA has merely exercised its discretion to establish rulemaking priorities, and chosen to first regulate those industries with the greatest demonstrated need.

45 Fed.Reg. 53286. Rejecting arguments of participants in the rulemaking proceeding that other workers, such as painters in the construction industry, are exposed to the same hazards as are workers in the manufacturing sector, the Secretary reasoned:

As stated previously, OSHA acknowledges that exposures to hazardous chemicals are occurring in other industries as well. A limited coverage of them is included in the final standard since all containers leaving the workplace of chemical manufacturers, importers, or distributors will be labeled, regardless of their intended destination. This will alert downstream users to the presence of hazardous chemicals, and the availability of material safety data sheets. The Agency contends that the focus of this standard should remain on the manufacturing sector since that is where the greatest number of chemical source injuries and illnesses are occurring. This focus will also serve to ensure that hazard information is being generated for chemicals produced or imported into this country, and this increased availability will benefit all industry sectors.

Id. The Secretary's reasoning does not address the petitioners' contention that reliance on the Standard Industrial Classification is inappropriate because it ignores the high level of exposure in specific job settings outside the manufacturing sector.

The Secretary maintains that section 6(g) of the Act affords him unreviewable discretion to determine what industries shall be covered by a standard. That section provides in relevant part:In determining the priority for establishing standards under this section, the Secretary shall give due regard to the urgency of the need for mandatory safety and health standards for particular industries, trades, crafts, occupations, businesses, workplaces or work environments.

29 U.S.C. Sec. 655(g) (1982). We reject the Secretary's contention that his priority-setting authority under section 6(g) vitiates judicial review of his determination that only the manufacturing industry need be covered by the Hazard Communication Standard. Section 6(g) must be read in conjunction with section 6(f), which provides for judicial review of standards. Indeed the language "due regard to the urgency of the need for mandatory safety standards for particular industries" suggests to us a statutory standard by which to measure the exercise of the Secretary's priority-setting discretion.2 In United Steelworkers of America v. Marshall, 647 F.2d 1189, 1309-10 (D.C.Cir.1980), cert. denied, 453 U.S. 913, 101 S.Ct. 3148, 69 L.Ed.2d 997 (1981) the court reviewed under section 6(f) the Secretary's decision to exempt the construction industry from a standard limiting exposure to lead. Although the court did not explicitly address section 6(g), it implicitly rejected the contention that the Secretary's priority-setting authority is unreviewable. We do so explicitly.

Our difficulty with the Secretary's reliance on section 6(g) arises from the Secretary's failure to explain why coverage of workers outside the manufacturing sector would have seriously impeded the rulemaking process. Section 6(g) clearly permits the Secretary to set priorities for the use of the agency's resources, and to promulgate standards sequentially. Once a standard has been promulgated, however, the Secretary may exclude a particular industry only if he informs the reviewing court, not merely that the sector selected for coverage presents greater hazards, but also why it is not feasible for the same standard to be applied in other sectors where workers are exposed to similar hazards. See United Steelworkers, 647 F.2d at 1309-10. The explanation for the Secretary's action quoted above is deficient in the latter respect. Thus the Secretary has failed to carry the burden of persuading us that section 6(g) justifies limitation of coverage to the manufacturing sector.

We are also unpersuaded by the Secretary's contention that the communication rule will "trickle down" to uncovered workers because containers will be labeled. Section 6(b)(5) requires that:

The Secretary, in promulgating standards dealing with toxic materials or other harmful physical agents ... shall set the standard which most adequately assures, to the extent feasible, on the basis of the best available evidence, that no employee will suffer material impairment of health or functional capacity even if such employee has regular exposure to the hazard dealt with by such standard for the period of his working