Hinkley groundwater contamination

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The town of Hinkley, California, located in the Mojave Desert, (about 121 miles driving distance north-northeast of Los Angeles) had its groundwater contaminated with hexavalent chromium starting in 1952, resulting in a legal case against Pacific Gas & Electric (PG&E) and a multimillion-dollar settlement in 1996.

The legal case was dramatized in the film Erin Brockovich, released in 2000.

Pollution of groundwater[edit]

A protest sign outside Hinkley town.

PG&E operates a compressor station in Hinkley for natural gas transmission pipelines. The natural gas has to be re-compressed approximately every 350 miles (560 km), and the station uses large cooling towers to cool the gas after it has been compressed.

Between 1952 and 1966, the water used in these cooling towers contained hexavalent chromium – now recognized as a carcinogen – to prevent rust in the machinery. The water was stored between uses in unlined ponds, which allowed it to percolate into the groundwater. This led to groundwater pollution, affecting soil and contaminating water wells near the compressor station, with a plume approximately 2 miles (3.2 km) long and nearly 1 mile (1.6 km) wide.[1]

Average hexavalent chromium levels in Hinkley were recorded as 1.19 parts-per-billion (ppb) with an estimated peak of 20 ppb. The PG&E Topock Compressor Station averaged 7.8 ppb and peaks at 31.8 ppb based on the PG&E Background Study.[2] The proposed California health goal for hexavalent chromium is 0.02 ppb.[3]

The US EPA sets the regulatory limit of total chromium at 100ppb.


Residents of Hinkley filed a class action against PG&E, encaptioned Anderson, et al. v. Pacific Gas and Electric (Superior Ct. for County of San Bernardino, Barstow Division, file BCV 00300.[4]

In 1993, Erin Brockovich, a legal clerk to lawyer Edward L. Masry, investigated the apparent elevated cluster of illnesses in the community linked to hexavalent chromium.[5] The efforts of Brockovich and Masry, and the plight of the people of Hinkley, became widely known when the film Erin Brockovich was released in 2000.

After many arguments, the case was referred to arbitration with maximum damages of $400 million. After the arbitration for the first 40 people resulted in roughly $110 million, PG&E reassessed its position and decided to end arbitration and settle the entire case. The case was settled in 1996 for $333 million, the largest settlement ever paid in a direct-action lawsuit in U.S. history.

In 2006, PG&E agreed to pay $295 million to settle cases involving another 1,100 people statewide for hexavalent chromium-related claims.

In 2008, PG&E settled the last of the cases involved with the Hinkley claims for $20 million.[6]


Ongoing cleanup documentation is maintained at the California Environmental Protection Agency (Cal/EPA) page regarding Hinkley.[7]

Samples taken in August 2010 showed that the plume of contaminated water had started to migrate into the lower aquifer.[8][9] As of September 2013, the Cal/EPA reports that some progress is being made on cleanup, but also reports that the plume has expanded to 6 miles long and 4 miles wide.[7]

A study released in 2010 by the California Cancer Registry showed that cancer rates in Hinkley "remained unremarkable from 1988 to 2008."[10] An epidemiologist involved in the study said that "the 196 cases of cancer reported during the most recent survey of 1996 through 2008 were less than what he would expect based on demographics and the regional rate of cancer."[10]

In June 2013 "Mother Jones" published an article discussing the work by the Center for Public Integrity that was critical of the study, and some others by the same researcher.[11]

Chromium(VI)-contaminated water supply is apparently a widespread problem, and is not isolated to Hinkley.[12]

See also[edit]


  1. ^ PG&E Hinkley Chromium Cleanup California Environmental Protection Agency, 9/10/08
  2. ^ PG&E Background Study
  3. ^ Baes, Michael (July 29, 2011). "Final Technical Support Document on Public Health Goal for Hexavalent Chromium in Drinking Water". Water. Oakland, CA: California Environmental Protection Agency. Retrieved April 23, 2012. The PHG [Public Health Goal] for hexavalent chromium is established at 0.02 parts per billion (ppb). 
  4. ^ http://environs.law.ucdavis.edu/volumes/26/2/banks.pdf
  5. ^ Baes, Michael (July 29, 2011). "Final Technical Support Document on Public Health Goal for Hexavalent Chromium in Drinking Water". Water. Oakland, CA: California Environmental Protection Agency. Retrieved April 23, 2012. The health-protective level is based on avoidance of potential carcinogenic effects. 
  6. ^ "PG&E settles last chromium(VI) case". Los Angeles Times. April 8, 2008. pp. B2. 
  7. ^ a b "PG&E Hinkley Chromium Cleanup". California Environmental Protection Agency. Retrieved 18 September 2013. 
  8. ^ A decade after "Erin Brockovich," contamination spreads in Hinkley, Victorville Daily Press, 2010-11-09, accessed 2010-11-17.
  9. ^ Carrie Kahn (2010-12-13). "Erin Brockovich II? Activist Returns To Aid Town". NPR. 
  10. ^ a b Schwartz, Naoki (2010-12-13) Survey shows unremarkable cancer rate in CA town, Boston Globe; J.W. Morgan and M.E. Reeves, Cancer in Hinkley: What was the real problem?
  11. ^ http://www.motherjones.com/environment/2013/05/erin-brockovich-hinkley-california-junk-science
  12. ^ Chromium-6 Is Widespread in US Tap Water, Environmental Working Group, 2010

External links[edit]

Coordinates: 34°54′09″N 117°09′39″W / 34.902567°N 117.1607°W / 34.902567; -117.1607