HAZWOPER scope and modeled hazardous-waste exposure

June 27, 1997
Ms. Mollie Netherland
CH2M HILL
[Recipient address omitted]
Dear Ms. Netherland:
This is in response to your inquiry to the Occupational Safety and Health Administration (OSHA) requesting clarification of the scope of OSHA's Hazardous Waste Operations and Emergency Response (HAZWOPER) Standard (29 CFR 1910.120). Please accept my apology for the long delay in finalizing this reply.
You stated in your inquiry that CH2M HILL employs a "worst-case exposure modeling" method to determine the worst-case airborne exposure levels of hazardous substances present on a specific work site. Your inquiry provided a brief description and sample applications of this modeling method and inquired whether OSHA would consider the results derived from this modeling method, coupled with the use of personal protective equipment (PPE) to protect employees against dermal hazards, as sufficient demonstration that no exposure or no reasonable possibility of exposure existed on a worksite and that, therefore, the HAZWOPER standard did not apply.
OSHA's position is that employee exposure to a hazardous substance should consider exposure by all routes of entry (inhalation, ingestion, and skin absorption) without regard to the use of PPE. Employees are considered "exposed" when they encounter any amount of hazardous substance(s) in the workplace environment that would cause harm to the employees.
Employers must comply with all the provisions of 29 CFR 1910.120(c) during the site characterization and analysis for evaluation of the site in regard to employee exposure or potential exposure during site operations. This evaluation includes the identification and evaluation of the safety and health hazards present on-site that may pose inhalation, ingestion or skin absorption hazards; hazards that are immediately dangerous to life or health; or other conditions that may cause death or serious harm. If the results of this evaluation indicates control procedures are not and will not be potentially necessary to protect employees from the identified safety and health hazards during site operations, then employees will not be considered to be exposed to the safety and health hazards. Those site operations with employees who are not exposed to or who could not be exposed to safety and health hazards are not within the scope of the applicability of the HAZWOPER standard and, therefore, the provisions of the requirements of 29 CFR 1910.120 are not applicable. The employer is, however, required to comply with all other applicable OSHA standards such as 29 CFR 1910 and 1926.
As indicated in your letter, the determination that no possibility for employee exposure to health and safety hazards must be documented. This documentation must be maintained on site and available for review by regulatory officials. In addition, the employer is required to maintain a vigilance for any change in exposure status of employees to safety and health hazards during site operations and to initiate protective measures if it is indicated that employees are or potentially could be exposed to these hazards on site.
As stated above, the HAZWOPER standard covers hazardous waste operations only where employees are exposed to or potentially exposed to safety or health hazards during the operation due to the release of hazardous substances in the worksite. Safety hazards from hazardous substances could include fire, explosion, corrosive action, etc. from flammables, explosives, corrosive materials, etc. associated with the site. Health hazards from hazardous substances could include cancer or organ function impairment from toxic, carcinogenic, or infectious materials associated with the site. Safety hazards from sources not specifically associated with the hazardous substances on the worksite such as trenching, moving machinery, slips, trips, and falls do not require coverage of the worksite under the HAZWOPER standard.
We hope this response provides the clarification you need. If you have further questions, please feel free to contact the [Office of Health Enforcement at (202) 693-2190].
Sincerely,
Stephen J. Mallinger, Acting Director
Office of Health Compliance Assistance
[Corrected 10/20/06]

[Requester letter reproduced on OSHA page; omitted here.]