Air Quality Life

Chromium on Periodic Table
Chromium on Periodic Table
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What is chromium-6?

It’s the only element to play a lead role in an Academy Award winning movie. Find out why here.

The metal element chromium (Cr) is an odorless, tasteless metallic element that occurs naturally in rocks, plants, soil, volcanic dust, humans, and animals. Chromium is a natural result of the erosion of chromium deposits.

Chromium-6 is the carcinogen made famous by the film "Erin Brockovich."

Chromium-6 (hexavalent chromium) is a compound form of the element that is produced by industrial processes. This heavy metal is considered a human carcinogen and is connected with a range of health issues. Chromium-6 exposure can occur through inhalation, ingestion, and skin contact.1 

Industrial pollution is the most common way chromium-6 is released into the environment, usually from leakage, poor storage, or inadequate disposal. It is readily soluble in water and has been known to infiltrate water sources.2

It’s also the carcinogen made famous by the film “Erin Brockovich,” which ended in a $333 million-settlement by Pacific Gas and Electric (PG&E). PG&E was found to have dumped roughly 370 million gallons of chromium-tainted wastewater into unlined ponds around Hinkley, Calif., poisoning the groundwater.3

What is chromium-6 used for?

Industrial uses of chromium-6 include stainless-steel production, welding, and torch-cutting. It is also used when applying and removing coatings that contain chromates, such as zinc chromate or lead chromate.4 In the Erin Brockovich case, PG&E used it as an additive to help rust prevention in cooling towers.

In the Erin Brockovich case, PG&E used chromium-6 as an additive to help rust prevention in cooling towers.

Metal chromium is used in making steel and other alloys. Concrete and other cement products usually contain chromium products, as do some pigments and dyes.

Chromium compounds, in either the chromium-3 or chromium-6 forms, are used for:

  • Chrome plating 
  • Manufacturing of dyes and pigments 
  • Preserving leather and wood
  • Treating cooling tower water
  • Drilling muds, textiles, copy machine toners5 

Chromium-6 in drinking water

Most often, public exposure happens from tainted groundwater.

Chromium-6 still contaminates the water of at least 200 million Americans in all 50 states.

In the Erin Brockovich case, PG&E used unlined ponds to store water containing chromium-6, and the toxin seeped into the groundwater used by residents. Chromium-6 still contaminates the water of at least 200 million Americans in all 50 states.

Studies show that drinking water with chromium-6 at even very low levels is linked to cancer.6 However, there is currently no U.S. federal regulation for any amount of chromium-6 allowed in tap water.

There is currently no U.S. federal regulation for any amount of chromium-6 allowed in tap water.

Researchers at the California Office of Environmental Health Hazard Assessment set a “public-health goal” of 0.02 parts per billion (ppb) of chromium-6 in tap water.7 The scientists determined 0.02 ppb is the level that would pose a negligible risk over a lifetime of consumption. After aggressive lobbying by industry and water utilities, state regulators adopted a legal limit 500 times the public health goal. It is the only enforceable drinking water standard at either the state or federal level in the U.S.8

Chromium-6 contaminated air

In addition to public exposure through drinking water, public exposure can occur from airborne chromium-6. For example, an aerospace supplier that finishes metal was forced to reduce its emissions when regulators traced unsafe, elevated levels of chromium-6 in the air back to their factory. The emissions were a result of the processes they used strengthen metal.9

People can be exposed to airborne chromium-6 through cigarette smoke, occupational hazards, living in environmentally impacted areas or from drinking contaminated groundwater. Airborne chromium-6 can cause lung cancer and other cancers – even at low exposure levels. It can be very irritating to the eyes, nose, throat, and skin, as well as cause rashes, runny noses, nosebleeds, sneezing, coughing, itching, and burning sensations. 

The U.S. Occupational Safety and Health Administration (OSHA) established an 8-hour, time-weighted average (TWA) exposure limit of 5 micrograms (µg) of chromium-6 per cubic meter of air (5 µg/m³). The National Institute for Occupational Safety and Health (NIOSH) recommends a 10-hour TWA exposure limit for all chromium-6 compounds of 1 µg/m³.10

Chromium-6 in the workplace

The most common way for workers to be exposed to chromium-6 is through inhalation.11

The U.S. Occupational Safety and Health Administration (OSHA) sets strict limits for airborne chromium-6 in the workplace. Annually, it is estimated that the number of workers exposed to chromium-6 is more than 558,000 workers in the United States, 786,000 in the European Union12, and 83,000 in Canada.13

Workplace exposures occur mainly in the following areas:

  • Welding and other "hot work" on stainless steel and other metals that contain chromium
  • Use of pigments, spray paints, and coatings
  • Operating chrome plating baths

Europe’s Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) passed regulations banning chromium-6 in Sept. 2017. However, the European Commission is considering lifting the ban to prevent companies that use chromium-6 from moving to China.14

How employers can protect workers from chromium-6 exposure 

OSHA requirements in the U.S. vary from state to state. For example, Oregon requires employers to abide by the following criteria:

  • Limit eight-hour time-weighted average hexavalent chromium exposure in the workplace to 5 micrograms or less per cubic meter of air.
  • Perform personal air monitoring at least every six months if initial monitoring shows worker exposure at or above the action level (2.5 micrograms per cubic meter of air calculated as an eight-hour time-weighted average).
  • Provide appropriate personal protective clothing and equipment when there is likely to be skin or eye contact.
  • Implement good personal hygiene and housekeeping practices to prevent hexavalent chromium exposure.
  • Prohibit employee rotation as a method to achieve compliance with the permissible exposure limit.
  • Provide respiratory protection as specified in the standard.15

It is especially important that employers provide required protection equipment and that workers are properly trained and compliant at using such equipment. 

How to protect yourself from chromium-6

Ways you can protect yourself from being exposed to chromium-6 through drinking water include:

  1. Test your water. Most commercial do-it-yourself home test kits do not offer a chromium-6 test. The best bet is to call a professional for lab testing.
  2. If you live in the U.S., you can search your zip code to learn about your local drinking water quality at
  3. Chromium-6 can be filtered from water by certified products that include reverse osmosis units. Visit for a list of qualified filters.

Steps you can take to help protect yourself from airborne chromium-6 exposure include:

  1. Source control: If you do any metal cutting, welding, or brazing, reducing the air contaminants at the source is your first line of defense. Be sure to wear a powerful half or full mask air respirator.
  2. Ventilation: Natural ventilation helps, but for particles of this nature, mechanical ventilation is recommended. Learn about the four types of mechanical ventilation here. In areas that contain higher amounts of chromium-6, ventilation without air cleaning may increase exposure. If you are in an area with such levels, use air cleaning with ventilation.
  3. Air cleaning: Chromium-6 does not require gas-phase filtration, as it is in the size range of fine and ultrafine particulate matter. Fine and ultrafine particles are well filtered by most IQAir systems and filters. Please use the Help Me Choose tool or contact a Commercial Applications Engineer to request a bid for your particular application. 

Hearing about the health risks from chromium-6 in the air and water can be alarming. However, with knowledge and preparation, you can rest assured you’re doing all you can to keep you and your family safe.

Air Quality Life is brought to you by The IQAir Group, the world’s leading innovator of Indoor Air Quality solutions since 1963. This online publication is designed to educate and inform the public about the latest research and news affecting indoor and outdoor air quality.

Article Resources

[1] U.S. Environmental Protection Agency. (2017). Chromium Compounds.

[2] U.S. Environmental Protection Agency. (2017). Chromium in Drinking Water. 

[3] Esquivel, P. (2015). 15 years after 'Erin Brockovich,' town still fearful of polluted water.

[4] Occupational Safety and Health Administration (OSHA). (2013). Hexavalent Chromium.

[5] U.S. Environmental Protection Agency. (2017). Chromium Compounds.

[6] Environmental Working Group. (2016). ‘Erin Brockovich’ Carcinogen in Tap Water of More Than 200 Americans.

[7] California EPA. (2014). Chromium-6 Drinking Water MCL.

[8] Environmental Working Group. (2016).

[9] Uranga, R. (2017). Long Beach company ordered to reduce hexavalent chromium emissions.

[10] OSHA. (2013). Hexavalent Chromium.

[11] Agency for Toxic Substances and Disease Registry (ATSDR). (2013). Chromium Toxicity: Who Is at Risk of Exposure to Chromium?

[12] Heederik, D. et al. (2017). SCOEL/REC/386 Chromium VI compounds.

[13] Proctor, D.M. (2015). Inhalation cancer risk assessment of hexavalent chromium based on updated mortality for Painesville chromate production workers. 

[14] Chemicals Technology. (2018). Banned Chromium VI likely to get regulatory approval in Europe.

[15] Oregon OSHA. (n.d.) Hexavalent Chromium Fact Sheet.

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