Agency for Toxic Substances and Disease Registry Case Studies in Environmental Medicine (CSEM)
Chromium Toxicity
Standards and Regulations
- 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.
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.
- 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.
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 |
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 |
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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