What Are Guidelines and Regulations for Carbon Tetrachloride Exposure?

After completing this section, you will be able to

• Describe current U.S. guidelines and regulations for carbon tetrachloride (CCl₄) exposure.

The U.S. government has developed regulations and guidelines for CCl₄. These are designed to protect workers and the U.S. public from potential adverse health effects from CCl₄ exposure. Table 1 summarizes the regulations and guidelines pertaining to CCl₄.

^*Note: At the time of publication of this CSEM, the listed guidelines and regulations were up to date. Guidelines and regulations are subject to change. For the most up-to-date information, see the following websites:

• Occupational Safety and Health Administration (OSHA): https://www.osha.gov/dsg/annotated-pels/tablez-2.html
• National Institute of Occupational Safety and Health (NIOSH): https://www.cdc.gov/niosh/
• Environmental Protection Agency (EPA): https://nepis.epa.gov

• Food and Drug Administration (FDA): https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=165.110

Air

The Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) is an 8-hour time-weighted average (TWA) of 10 parts per million (ppm) in workplace air. This is the highest level of CCl₄ in air to which a worker may be exposed, averaged over an 8-hour workday for up to a 40-hour workweek.

The National Institute for Occupational Safety and Health (NIOSH) recommends a 60-minute time-weighted average (TWA) short-term exposure limit (STEL) of 2 ppm [NIOSH 2005]. The NIOSH immediately dangerous to life and health (IDLH) value for CCl₄ is 200 ppm.

The American Conference of Governmental Industrial Hygienists (ACGIH) recommends an 8-hour TWA of 5 ppm and a 15-minute STEL of 10 ppm [ACGIH 2017].

Air

CCl₄ is on the list of 187 hazardous air pollutants listed in the Clean Air Act. The U.S. Environmental Protection Agency (EPA) classifies CCl₄ as a hazardous air pollutant [EPA 2014].

Water

The EPA maximum contaminant level (MCL) for CCl₄ in drinking water is 5 ppb [EPA 2008].

Federal regulations have banned the use of all pesticide products containing CCl₄. An exception is the use of CCl₄ on encased museum specimens.

Food

The U.S. Food and Drug Administration (FDA) classifies carbon tetrachloride as an indirect food additive for use only as a component of adhesives. FDA also monitors bottled water and uses a level of 5 μg/L as acceptable for bottled water [FDA, 2017].

Table 1. Regulations and Guidelines for Carbon Tetrachloride

^*TLV-TWA (threshold limit value-time-weighted average) – ACGIH TLVs are listed in the order of 8-hour time-weighted averages (TWAs during a 40-hour workweek, unless otherwise indicated), short-term exposure limits, and ceilings levels, if available. A TLV is a level to which it is believed a worker can be exposed day-after-day for a working lifetime without adverse health effects. These are not regulatory limits unless OSHA adopts them as a PEL.

^†STEL (short-term exposure limit) – Unless noted otherwise, the STEL is a 15-minute TWA maximum exposure that should not be exceeded at any time during a workday (a single work shift) to prevent adverse health effects.

^‡ REL (recommended exposure limit) – NIOSH RELs are for up to 10-hour TWAs during up to a 40-hour work week, unless otherwise indicated (can also be a STEL or ceiling limit). These are not regulatory limits.

^§PEL (permissible exposure limit) – OSHA PELs are 8-hour TWAs, unless otherwise indicated (can also be short-term exposure limits (STEL) or ceiling limits). The PEL represents an employee’s average airborne exposure in any 8-hour work shift of a 40-hour work week, which shall not be exceeded. OSHA enforces these limits under section 5(a)(2) of the Occupational Safety and Health Act. The 8-hour TWA PEL is the level of exposure established as the highest level of exposure an employee may be exposed to without incurring the risk for adverse health effects.

^¶Ceiling limit – A ceiling limit, unless otherwise noted, is a maximum concentration level of exposure that should not be exceeded at any time during a workday in an effort to prevent adverse health effects.

^**MCL (maximum contaminant level) – The highest level of a contaminant that is allowed in drinking water.

• The U.S. government has developed regulations and guidelines for CCl₄.