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Groundwater Contamination with Chromium-6 in Hinkley, California


In 1952, the Pacific Gas and Electric Company (PG&E) installed a compressor station near the town of Hinkley in San Bernardino County, CA  part of a gas pipeline system linking Texas to California. Since then, the company has used a carcinogenic chemical compound named chromium-6 as a corrosion inhibitor in its cooling system. The contaminated water was discharged into unlined pools, thus leaking to the aquifer serving Hinkley’s residents water needs. The leakage occurred (at least) from 1952 to 1972, the year PG&E lined the discharging pools. However, it was not until 1977 that the California state passed a Law regulating the use of chromium-6 and limiting its concentration in water to 50 µg/L.

Chromium-6 is known for causing damage to several organs and different types of cancer. Moreover, the compound also modifies human DNA, which can prolong the effects of exposure to future generations. Local residents experienced several symptoms associated with chromium-6 contamination including prostate, cervical, breast and stomach cancers and respiratory problems. In 1987, PG&E officials informed the state of California of high levels on chromium-6 in underground water north of the discharge ponds. The levels were 10 times greater than the limits established by CA’s 1977 regulation. At that time, PG&E started buying properties affected by pollution. Yet, company officials told citizens the water was suitable for both drinking and agriculture.

Erin Brockovich, a clerk at ‘Masry and Vititoe’ Law firm, came across records on PG&E’s offers to buy Hinkley’s citizens properties while filing them. The fact that these documents were mixed with residents medical records raised Brockovich’s attention. The clerk decided to investigate the case and ended up convincing some of the people affected by contamination (and the lawyers she was working to) to start legal action against PG&E in 1993. Initially, there were 77 plaintiffs but the numbers raised to 648.

While PG&E lawyers tried to de-link people’s health problems from exposure to chromium-6, the plaintiffs showed that the company knew the contamination at least since 1965 and did nothing. PG&E eventually managed to take the case out of courts and reach a settlement through mediation. In 1996, PG&E agreed to pay the plaintiffs a total of 333 million dollars, to end the use of chromium-6 in its cooling system and to clean up the environment.

After several unsuccessful attempts (the contaminated plume kept growing) to clean up the contaminated aquifer, PG&E started buying people’s houses in 2012 and destroying them to avoid squatting. Two-thirds of the residents in the affected area agreed and moved elsewhere causing Hinkley’s population to fall considerably. Later studies by the California Cancer Registry stated that cancer figures in Hinkley weren’t abnormal in the period 1988-2006. However, the Center for Public Integrity questioned the validity of the findings due to methodology problems, exclusion of the most serious cases and lack of independence between researchers and the chemical industry lobby. 

Basic Data

Name of conflict:Groundwater Contamination with Chromium-6 in Hinkley, California
Country:United States of America
State or province: Hinkley, California
Location of conflict:Mojave Desert
Accuracy of locationHIGH (Local level)

Source of Conflict

Type of conflict. 1st level:Industrial and Utilities conflicts
Type of conflict. 2nd level:Water access rights and entitlements
Oil and gas exploration and extraction
Landfills, toxic waste treatment, uncontrolled dump sites
Transport infrastructure networks (roads, railways, hydroways, canals and pipelines)
Water treatment and access to sanitation (access to sewage)
Specific commodities:Natural Gas

Project Details and Actors

Project details

-In July 2014 California became the first state to acknowledge that ingested chromium-6 is linked to cancer and as a result has established a maximum Chromium-6 contaminant level (MCL) of 10 parts per billion (ppb)

-Hexavalent chromium was an additive that prevented rust in the gas cooling towers, and it was disposed of in nearby pools. Under ideal circumstances, the dangerous heavy metals would be filtered out and reclaimed.

Type of populationUrban
Start of the conflict:1987
Company names or state enterprises: Pacific Gas and Electric Company (PG&E) from United States of America
Relevant government actors:Agency for Toxic Substances and Disease Registry (ATSDR); California Environmental Protection Agency (Cal/EPA); California Department of Public Health; National Toxicology Program (NTP); California Cancer Registry.
Environmental justice organizations (and other supporters) and their websites, if available:Local residents of Hinkley
Supporters: The Law Offices of Masry and Vititoe

Conflict & Mobilization

IntensityHIGH (widespread, mass mobilization, violence, arrests, etc...)
Reaction stageMobilization for reparations once impacts have been felt
Groups mobilizing:Neighbours/citizens/communities
Local scientists/professionals
The town of Hinkley residents
Erin Brockovich
Forms of mobilization:Community-based participative research (popular epidemiology studies, etc..)
Lawsuits, court cases, judicial activism
Media based activism/alternative media
Official complaint letters and petitions
Public campaigns
Appeals/recourse to economic valuation of human health damage


Environmental ImpactsVisible: Air pollution, Biodiversity loss (wildlife, agro-diversity), Fires, Loss of landscape/aesthetic degradation, Soil contamination, Waste overflow, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion
Potential: Food insecurity (crop damage), Global warming
Health ImpactsVisible: Exposure to unknown or uncertain complex risks (radiation, etc…), Mental problems including stress, depression and suicide, Deaths
Potential: Malnutrition
Socio-economical ImpactsVisible: Increase in Corruption/Co-optation of different actors, Displacement, Loss of livelihood, Violations of human rights, Loss of landscape/sense of place


Project StatusStopped
Conflict outcome / response:Compensation
Institutional changes
Court decision (victory for environmental justice)
New legislation
Technical solutions to improve resource supply/quality/distribution
Project cancelled
Proposal and development of alternatives:Specific demands: Decontamination and monetary compensation to affected people.
Do you consider this an environmental justice success? Was environmental justice served?:Not Sure
Briefly explain:The case settlement ended up in monetary compensation for the plaintiffs, but several people died before 1996 and many victims weren't included in the settlement. PG&E was unable to contain the plume of polluted water, forcing an exodus from the exposed areas. The area will be inhabitable until someone finally solves the problem. PG&E had to clean up the contaminated groundwater and stop using chromium-6. By 2013 PG&E had spent over $750 million on remediation. However, the town remained polluted and Hinkley is a ghost town now.

Sources & Materials

References to published books, academic articles, movies or published documentaries

Environmental Justice Litigation in California: How Effective is Litigation in Addressing Slow Violence?


The Town Erin Brockovich Rescued Is Basically a Ghost Town Now





PG&E Hit With Class Action Lawsuit Over Lingering Hinkley Contamination

Survey shows unremarkable cancer rate in CA town

Cancer-cluster study seeking to debunk 'Erin Brockovich' has glaring weaknesses

Story Behind Erin Brockovich

Related media links to videos, campaigns, social network

Erin Brockovich

Other comments:This particular case became very famous in 2000 when the movie "Erin Brockovich" with Julia Roberts was released.

Meta information

Contributor:ENVJustice Project
Last update18/08/2019



Protesters in Hinkley


Hinkley, California

Source: Mike Pearl