In a recent case, Seward Ship's Drydock,Inc.,^[1] the US Court of Appeals for the Ninth Circuit held that § 1910.134(d) of the OSHA Respiratory Protection Standard requires an evaluation of respiratory hazards to determine whether a respirator is required as well as to select an appropriate respirator after a determination has been made that one is required. In practical effect, the decision means Section 1910.134(d) imposes the following requirements on employers:

Whenever it is reasonable to suspect that an employee may be exposed to concentrations of airborne contaminants at levels where a respirator would be necessary to protect the health of the employee, the employer must evaluate the work environment so that exposures to the employee can be determined or reasonably estimated. In these situations, where the employer cannot identify or reasonably estimate the employee exposure, the employer must consider the atmosphere to be IDLH.

Based on OSHA's more recent substance-specific standards and the preamble to the final rule adopting the amended Respiratory Protection Standard, it appears that an assessment may be based on data from industry-wide surveys, mathematical analysis, or historical monitoring. While this interpretation of § 1910.134(d) may appear to reflect obvious best practice, it seems likely to result in more formal, documented evaluations and additional exposure monitoring.

This case before the 9th Circuit was an appeal brought by the Secretary of Labor from an adverse decision of the Occupational Safety and Health Review Commission ("Review Commission"). The issue on appeal was whether § 1910.134(d) required evaluation of respiratory hazards only after a determination had been made that respirators were necessary (the Review Commission position) or whether an evaluation of respiratory hazards was required to determine whether a respirator was necessary and then to select the appropriate respirator (OSHA's position). Under the Review Commission's interpretation, a citation could be issued by OSHA for failure to select and use a required respirator, but not for failure to evaluate the need for a respirator.

After the Review Commission determined that an evaluation of respiratory hazards was required only after a determination had been made that respirators were necessary, it turned to the issue of whether OSHA had demonstrated that respirators were necessary. Two Commissioners concluded that OSHA had failed to prove that respirators were necessary and, therefore, that the employer was not required to perform an evaluation of the respiratory hazards under § 1910.134(d). They based that conclusion on the fact that OSHA failed to prove air contaminant levels exceeded the applicable permissible exposure limits (PELs) or that there was a significant risk of exposure in excess of the PELs. The third Commissioner dissented on this issue, concluding that OSHA had established that respirators were necessary because grab sample monitoring revealed exposure levels close to the PELs and the ventilation used by the employer was unreliable. Based on that finding, the dissenting Commissioner reasoned that an evaluation of respiratory hazards under §1910.134 would have been required.

In reversing the holding of the Review Commission, the Ninth Circuit held that OSHA's Respiratory Protection Standard requires employers to evaluate potentially harmful atmospheres to determine whether respirators are required and in selecting the appropriate respirator, rather than performing this evaluation after a determination has been made that respirators are necessary. In reaching its decision, the Court looked to the overall purpose of the Respiratory Protection Standard and concluded the standard was not ambiguous and that the Review Commission had given excessive weight to the fact that the provision requiring the employer to identify and evaluate the respiratory hazard(s) in the workplace was in the section of the standard titled "Selection of Respirators."

In light of this opinion, employers should re-evaluate their procedures for determining when it is reasonable to suspect that an employee may be exposed to harmful concentrations of airborne contaminants, and for evaluating potential exposures based on anticipated workplace conditions and reasonably foreseeable emergencies (e.g., ventilation failure). This opinion suggests the possibility that OSHA may attempt to make greater use of the Respiratory Protection Standard rather than the General Duty Clause to address allegedly harmful airborne contamination that is not addressed by a PEL or is below a current PEL.

_{[1] Secretary Of Labor v. Seward Ship's Drydock,Inc., No. 18-71216 (September 11, 2019).}