Agency for Toxic Substances and Disease Registry 
Case Studies in Environmental Medicine (CSEM) 
Toxicity of Polycyclic Aromatic Hydrocarbons (PAHs)
What are the Standards and Regulations for PAHs Exposure?

Learning Objectives

Upon completion of this section, you will be able to

• describe the Occupational Safety and Health Administration’s (OSHA) Permissible Exposure Level (PEL) for PAH, and
• describe the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level (MCL) for PAH in drinking water.

Introduction

U.S. government agencies have established standards that are relevant to PAHs exposures in the workplace and the environment. There is

• a standard relating to PAH in the workplace, and
• a standard for PAH in drinking water.

Workplace

OSHA has not established a substance-specific standard for occupational exposure to PAHs. Exposures are regulated under OSHA's Air Contaminants Standard  for substances termed coal tar pitch volatiles (CTPVs) and coke oven emissions. Employees exposed to CTPVs in the coke oven industry are covered by the coke oven emissions standard.

The OSHA coke oven emissions standard requires employers to control employee exposure to coke oven emissions by the use of engineering controls and work practices. Wherever the engineering and work practice controls which can be instituted are not sufficient to reduce employee exposures to or below the permissible exposure limit, the employer shall nonetheless use them to reduce exposures to the lowest level achievable by these controls and shall supplement them by the use of respiratory protection. The OSHA standard also includes elements of medical surveillance for workers exposed to coke oven emissions.

Air

The OSHA PEL for PAHs in the workplace is 0.2 milligram/cubic meter (mg/m³).

The OSHA-mandated PAH workroom air standard is an 8–hour time-weighted average (TWA) permissible exposure limit (PEL) of 0.2 mg/m³, measured as the benzene-soluble fraction of coal tar pitch volatiles. The OSHA standard for coke oven emissions is 0.15 mg/m³. The National Institute for Occupational Safety and Health (NIOSH) has recommended that the workplace exposure limit for PAHs be set at the lowest detectable concentration, which was 0.1 mg/m³ for coal tar pitch volatile agents at the time of the recommendation. Table 1 summarizes relevant exposure criteria for PAHs.

Workplace Standards

^*TLV: threshold limit value.

^†TWA (time-weighted average): concentration for a normal 8-hour workday and a 40-hour workweek to which nearly all workers may be repeatedly exposed.

^‡REL (recommended exposure limit): recommended airborne exposure limit for coal tar pitch volatiles (cyclohexane-extractable fraction) averaged over a 10-hour work shift.

^§PEL (permissible exposure limit): the legal airborne permissible exposure limit (PEL) for coal tar pitch volatiles (benzene soluble fraction) averaged over an 8-hour work shift.

^¶MCL: maximum contaminant level.

Environmental Standards

Water

The maximum contaminant level goal for benzo(a)pyrene in drinking water is 0.2 parts per billion (ppb).

In 1980, EPA developed ambient water quality criteria to protect human health from the carcinogenic effects of PAH exposure. The recommendation was a goal of zero (nondetectable level for carcinogenic PAHs in ambient water). EPA, as a regulatory agency, sets a maximum contaminant level (MCL) for benzo(a)pyrene, the most carcinogenic PAH, at 0.2 ppb. EPA also sets MCLs for five other carcinogenic PAHs (see Table 1).

For more information on EPA rules and regulations regarding PAH, visit EPA’s Web site at www.epa.gov.

Food

The U.S. Food and Drug Administration has not established standards governing the PAH content of foodstuffs.

Key Points

• OSHA’s PEL for PAH in the workplace is 0.2 mg/m³ for benzene-soluble coal tar pitch fraction of air (8-hour TWA).
• OSHA requires workers to be trained in the proper use of appropriate personal protective equipment (PPE) and safety.
• Workers must receive medical surveillance if exposed above the PEL.
• EPA’s maximum contaminant level (MCL) for PAH in drinking water is 0.2 ppb of drinking water.

Progress Check