Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM)

Chromium Toxicity
Standards and Regulations

Workplace

Air

OSHA mandates a ceiling concentration of 100 µg CrO₃/m³ for chromic acid and chromates.

The Occupational Safety and Health Administration (OSHA) mandated a permissible exposure limit (PEL) ceiling of 100 µg CrO₃/m³ for chromic acid and chromates. For Cr (II) and Cr (III) salts, the PEL is an 8-hour time-weighted average (TWA) of 500 µg Cr/m³. For chromium metal and for insoluble salts, the TWA is 1,000 µg Cr/m³.

The National Institute for Occupational Safety and Health (NIOSH) has recommended a 10-hour TWA exposure limit of for all Cr (VI) compounds of 1 µg Cr (VI)/m³. For chromium metal and Cr (II) and Cr (III) compounds, the recommended exposure limit is 500 µg Cr (VI)/m³ as a 10-hour TWA.

On the basis of current evidence, NIOSH considers all Cr (VI) compounds potentially carcinogenic.

Environment

Air

EPA regulates chromium emissions under the Clean Air Act of 1990. EPA uses technology-based standards for categories of industries, rather than numerical emission standards, to reduce chromium levels in ambient air. These maximum achievable control technology (MACT) standards are based on emissions levels already achieved by the best-performing similar facilities.

Drinking Water

The current maximum contaminant level for chromium in drinking water is 100 µg/L.

EPA has an enforceable maximum contaminant level of total chromium in drinking water of 100 µg/L (100 ppb) for public water systems.

Table 1 summarizes the U.S. standards and regulations for chromium salts.

Table 1. Standards and Regulations for Chromium

Agency	Focus	Level	Comments
American Conference of Governmental Industrial Hygienists	Air: workplace	10 µg/m³ as Cr	Advisory; TWA ^* to avoid carcinogenic risk from insoluble Cr (VI) compounds
		50 µg/m³ as Cr	TWA for water-soluble Cr (VI) compounds
		500 µg/m³ as Cr	TWA for chromium metal and Cr(III) compounds
National Institute for Occupational Safety and Health	Air: workplace	1 µg/m³ as Cr	Advisory; TWA (10-hour) for chromic acid and all Cr (VI) salts
National Institute for Occupational Safety and Health	Air: workplace	500 µg/m³as Cr	Advisory; TWA (10-hour) for chromium metal and Cr (II) and Cr (III) salts
Occupational Safety and Health Administration	Air: workplace	100 µg/m³ as CrO₃	Regulation; PEL^† for chromic acid and chromates (ceiling)
		500 µg/m³ as Cr	PEL for Cr (II) and Cr (III) salts (8-hour TWA)
		1,000 µg/m³ as Cr	PEL for chromium metal and insoluble salts (8-hour TWA)
U.S. Environmental Protection Agency	Air: environment	Not applicable	Chromium is listed as a hazardous pollutant
U.S. Environmental Protection Agency	Drinking water	100 µg/L	Regulation; current MCL ^‡ for total chromium
*TWA (time-weighted average): TWA concentration for a normal workday and a 40-hour workweek to which nearly all workers may be repeatedly exposed. †PEL (permissible exposure limit): highest level of chromium in air to which a worker may be exposed, averaged over an 8-hour workday. ‡MCL (maximum contaminant level) enforceable level for drinking water.

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Revised 2000-07-06.

Agency for Toxic Substances and Disease RegistryCase Studies in Environmental Medicine (CSEM) Chromium Toxicity Standards and Regulations

Workplace

Air

Environment

Air

Drinking Water

Table 1. Standards and Regulations for Chromium

Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM)

Chromium Toxicity
Standards and Regulations