Why did PG&E use hexavalent chromium?
Between 1952 and 1966, PG&E used hexavalent chromium, also known as chromium 6, to fight corrosion in cooling tower water. The wastewater from the cooling towers was discharged to unlined ponds at the site. Some of the wastewater percolated to the groundwater, resulting in hexavalent chromium pollution.
What is hexavalent chromium?
Hexavalent chromium ( chromium (VI), Cr (VI), chromium 6) is chromium in any chemical compound that contains the element in the +6 oxidation state (thus hexavalent ). Virtually all chromium ore is processed via hexavalent chromium, specifically the salt sodium dichromate.
Why is there hexavalent chromium in cooling towers?
Between 1952 and 1966, the water in the 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.
What is the proposed California health goal for hexavalent chromium?
The proposed California health goal for hexavalent chromium was 0.02 ppb in 2011. In 1991, when the EPA raised the federal MCL for total chromium to 100 ppb, California remained at 50 ppb.
Why is Erin Brockovich associated with chromium?
Hexavalent chromium — known more commonly as chromium-6 or “the Erin Brockovich chemical” — gained international notoriety in the 1990s, after Brockovich discovered that it was contaminating drinking water and making people sick in the San Bernardino County town of Hinkley, Calif.
Why did PG&E even tell the citizens of Hinkley about the chromium?
Why did PG&E even tell the citizens of Hinkley about the chromium? They did this to establish a statute of limitations and in a case of this, you'd have a year to file a lawsuit. So they thought to "let the cat out of the bag" and if they could ride out the whole year without suing, then they'd be okay.
What happened Pacific Gas & Electric chromium contamination?
From 1952 to 1966, Pacific Gas and Electric Company (PG&E) dumped about 370 million gallons (1,400 million litres) of chromium-tainted wastewater into unlined wastewater spreading ponds around the town of Hinkley, California, located in the Mojave Desert about 120 miles north-northeast of Los Angeles.
How did the groundwater in Hinkley get contaminated?
Hinkley was a small farming community in the 1990s when residents learned that groundwater was polluted with chromium 6, a cancer-causing heavy metal. It had seeped into the water after being dumped into unlined ponds at the utility company's compressor station in the 1950s and '60s.
What are the bad effects of hexavalent chromium to the health of people living in Hinkley?
Repeated exposure to hexavalent chromium can cause a number of respiratory conditions, including asthma, bronchitis, itching, physical trauma to the respiratory tract, and lung cancer. Real-life Hinkley has been all but abandoned since Erin Brockovich was in theaters.
Why did Pacific Gas & Electric PG&E use hexavalent chromium at its Hinkley facility explain the chemistry involved?
Between 1952 and 1966, PG&E used hexavalent chromium, also known as chromium 6, to fight corrosion in cooling tower water. The wastewater from the cooling towers was discharged to unlined ponds at the site. Some of the wastewater percolated to the groundwater, resulting in hexavalent chromium pollution.
What was the chemical in Erin Brockovich?
Even with on-going clean-up efforts, hexavalent chromium (also known as chromium-6, a chemical that has been shown to cause lung cancer when inhaled by humans) still haunts the plaintiffs, as the plume continued to spread.
Was the movie Erin Brockovich accurate?
On her website, Brockovich says the film is "probably 98% accurate". While the general facts of the story are accurate, there are some minor discrepancies between actual events and the movie, as well as a number of controversial and disputed issues more fundamental to the case.
What was PG&E found guilty of?
Pacific Gas & Electric pleaded guilty on Tuesday to 84 separate counts of involuntary manslaughter and one felony count of unlawfully starting a fire in a case stemming from a horrific 2018 blaze that destroyed much of the town of Paradise in Northern California.
What did PG&E do wrong?
In April, Sonoma County's district attorney charged PG&E with five felonies and 28 misdemeanors, including recklessly causing a fire with great bodily injury, in connection with the Kincade fire, which damaged or destroyed more than 400 buildings and seriously injured six firefighters in 2019.
Is Hinkley water still contaminated?
Tests reveal that the cancer-causing toxin has been detected more than a half-mile beyond the previous known boundary of contamination, a scandal that plagued the town of Hinkley and formed the basis for the movie Erin Brockovitch a decade ago.
What is hexavalent chromium used for?
Hexavalent chromium is used in textile dyes, wood preservation, anti-corrosion products, chromate conversion coatings, and a variety of niche use s. Industrial uses of hexavalent chromium compounds include chromate pigments in dyes, paints, inks, and plastics; chromates added as anticorrosive agents to paints, primers, ...
What is the OSHA PEL for hexavalent chromium?
In the U.S., the OSHA PEL for airborne exposures to hexavalent chromium is 5 μg/m 3 (0.0050 mg/m 3 ). The U.S. National Institute for Occupational Safety and Health proposed a REL of 0.2 µg/m 3 for airborne exposures to hexavalent chromium. Hexavalent chromium is present in drinking water and public water systems.
How is chromate transported into cells?
Due to its structural similarity to sulfate, chromate (a typical form of chromium (VI) at neutral pH) is transported into cells via sulfate channels. Inside the cell, hexavalent chromium (VI) is reduced first to pentavalent chromium (V) then to trivalent chromium (III) without the aid of any enzymes.
What is a chromium compound?
An example of a chromium (VI) compound: chromium trioxide. Hexavalent chromium ( chromium (VI), Cr (VI), chromium 6) is chromium in any chemical compound that contains the element in the +6 oxidation state (thus hexavalent ). Virtually all chromium ore is processed via hexavalent chromium, specifically the salt sodium dichromate.
Why do we use chromium primer?
Since World War II, the U.S. Army relied on hexavalent chromium compounds to protect its vehicles, equipment, aviation and missile systems from corrosion. The wash primer was sprayed as a pretreatment and protective layer on bare metal.
How does chromium reduction occur?
The reduction occurs via direct electron transfer primarily from ascorbate and some nonprotein thiols. Vitamin C and other reducing agents combine with chromate to give chromium (III) products inside the cell. The resultant chromium (III) forms stable complexes with nucleic acids and proteins.
What are the risks of chromium?
Workers who are exposed to hexavalent chromium are at increased risk of developing lung cancer, asthma, or damage to the nasal epithelia and skin.
What is hexavalent chromium?
Overview. Hexavalent chromium [Cr (VI)] is one of the valence states (+6) of the element chromium. It is usually produced by an industrial process. Cr (VI) is known to cause cancer. In addition, it targets the respiratory system, kidneys, liver, skin and eyes.
Why is chromium added to steel?
Chromium metal is added to alloy steel to increase hardenability and corrosion resistance. A major source of worker exposure to Cr (VI) occurs during "hot work" such as welding on stainless steel and other alloy steels containing chromium metal.
What industrial processes produce hexavalent chromium?
Some of the industrial processes that can produce hexavalent chromium include: Coatings containing chromates: dyes, paints, inks & plastics. Metallic chromium in the feedstock may be converted to the hexavalent form. Hexavalent chromium may be present in a feedstock containing any form of chromium.
How to clean up hexavalent chromium?
Of the 4 ways to clean up surface contamination (sweeping, blowing with compressed air, wet mopping, and vacuuming), wet mopping and HEPA vacuuming are the only ways that are effective and acceptable.
What is the most toxic form of chromium?
Hexavalent Chromium is the most toxic form of chromium. Reading through articles and publications, you will see hexavalent chromium identified in different ways, including: Hex Chrome, Chrome VI, CrVI and Cr 6+.
What is the maximum exposure level for hexavalent chromium?
The new Permissible Exposure Level (PEL) for hexavalent chromium is 5 µg/m3 in an 8-hr shift. This PEL of 5 µg/m3 was reduced from 52 µg/m3. A factor of 10!
What are the symptoms of chromium?
A worker exposed to hexavalent chromium may experience symptoms such as sinus irritation, nosebleeds, ulcers (stomach and nose), skin rash, chest tightness, wheezing and shortness of breath.
Can hexavalent chromium be exposed?
If your company has a process that could be producing hexavalent chromium, workers can be exposed through many sources.
Is hexavalent chromium a part of dust?
Remember that hexavalent chromium is usually only a percentage of the dust fume and mist generated, and other processes will produce fume containing small amounts of hexavalent chromium. Be advised it is entirely possible that one could exceed the TLV for hexavalent chromium while staying under the TLV for other fumes given off.
What is chromium 6?
PG&E used chromium 6, or hexavalent chromium (a cheap and efficient rust suppressor), in its compressor station for natural-gas transmission pipelines. Hexavalent-chromium compounds are genotoxic carcinogens . In 1993, legal clerk Erin Brockovich began an investigation into the health impacts of the contamination.
Who was the scientist who found the link between Chromium 6 and cancer?
Protest sign outside Hinkley. During negotiations, the presiding judges told PG&E's lawyers that a 1987 study by Chinese scientist Jian Dong Zhang reporting a strong link between chromium 6 pollution and cancer in humans would be "influential" in their decision.
How wide is the Chromium plume?
In September 2013, CalEPA reported that the plume had expanded to 6 miles (9.7 km) long and 4 miles (6.4 km) wide. In 2015, the California Regional Water Quality Control Board, Lahontan Region served PG&E with an order to clean up the effects of the chromium discharge. At the time of the report, the plume was "8 miles (13 km) in length and approximately 2 miles (3.2 km) in width, throughout the Hinkley Valley and into Harper Dry Lake Valley."
Why is the water in the cooling towers considered a carcinogen?
Between 1952 and 1966, the water in the 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 originally about 2 miles (3.2 km) long and nearly 1 mile (1.6 km) wide. By 2013, the plume was 6 miles (9.7 km) long and nearly 2 miles (3.2 km) wide.
When was ChemRisk published?
ChemRisk updated his analysis and published it in April 1997 Journal of Occupational and Environmental Medicine (JOEM, the official publication of the American College of Occupational and Environmental Medicine) as a retraction of Zhang's 1987 paper.
Who is the Senator who called the Senate hearing on Chromium VI?
Two years later, Senator Deborah Ortiz (who represented the Sacramento area and chaired the Senate Health and Human Services Committee) called a Senate hearing about "Possible Interference in the Scientific Review of Chromium VI Toxicity".
What happened to PG&E after the Blue-Ribbon Panel Report came out?
After the blue-ribbon panel report came out, PG&E came into court, and they told the judge that everything had changed. They were waving the blue-ribbon report—the blue-ribbon panel report—like a flag. They said to the judge, the State of California has spoken. It has said that chromium VI does not cause cancer by ingestion, and they wanted to amend their paperwork, their motions, their declarations, and move to dismiss our case. And they got that permission to do that. They amended all their paperwork, and we were given permission to take discovery—to take depositions, issue subpoenas—and we have obtained thousands of pages of documents in connection with the blue-ribbon panel process.
Hinkley Compressor Station Chromium Contamination Cleanup
PG&E's natural gas Compressor Station is located approximately two miles southeast of the town of Hinkley and a dozen miles west of Barstow in the Mojave Desert of San Bernardino County. Between 1952 and 1966, PG&E used hexavalent chromium, also known as chromium 6, to fight corrosion in cooling tower water.
Announcements
Issuance of a New Notice of Applicability of General Waste Discharge Requirements for In-Situ Remediation Zones and the Freshwater Injection Systems (Board Order No. R6V-2008-0014), Pacific Gas and Electric Company's Hinkley Compressor Station, San Bernardino County - dated October 5, 2021 (165 page document)
Water Board Orders
Issuance of a New Notice of Applicability of General Waste Discharge Requirements for In-Situ Remediation Zones and the Freshwater Injection Systems (Board Order No. R6V-2008-0014), Pacific Gas and Electric Company's Hinkley Compressor Station, San Bernardino County - dated October 5, 2021 (165 page document)
Other Documents and Information
Dr. John Izbicki of the USGS is leading scientific studies to determine the range of natural and anthropogenic (human-caused) chromium in the Hinkley Valley. Field work for the background study began in March 2015. The link below will take you to the USGS’s webpage for the Hinkley project: http://ca.water.usgs.gov/projects/hinkley/
Overview
Exposure and safety issues
Hexavalent chromium is a constituent of tobacco smoke.
Hexavalent chromium was released from the Newcastle Orica Koorgang Island ammonium nitrate plant on August 8, 2011. The incident occurred when the plant entered the 'start up' phase after the completion of a five-yearly maintenance overhaul. The "High Temperature Shift catalyst began the process of 'reduction'" where steam passes through the catalyst bed and out the SP8 vent st…
Toxicity
Hexavalent chromium compounds are genotoxic carcinogens. Due to its structural similarity to sulfate, chromate (a typical form of chromium(VI) at neutral pH) is transported into cells via sulfate channels. Inside the cell, hexavalent chromium(VI) is reduced first to pentavalent chromium(V) then to trivalent chromium(III) without the aid of any enzymes. The reduction occurs via direct electron transfer primarily from ascorbate and some nonprotein thiols. Vitamin C and other reducin…
Remediation of hexavalent chromium in groundwater and drinking water
There are mainly three types of methods to remediate hexavalent chromium in ground water and drinking water:
1. Reduction of toxicity;
2. Removal technologies; and;
3. Containment technologies
See also
• California Proposition 65 (1986)
External links
• ATSDR Case Studies in Environmental Medicine: Chromium Toxicity U.S. Department of Health and Human Services
• Hexavalent Chromium National Emphasis Program
• Economou-Eliopoulos, Maria; Megremi, Ifigenia; Vasilatos, Charalampos (2011). "Factors controlling the heterogeneous distribution of Cr(VI) in soil, plants and groundwater: Evidence from the Assopos basin, Greece". Chemie der Erde – Geochemistry. 71 (1): 39–52. Bi…
• ATSDR Case Studies in Environmental Medicine: Chromium Toxicity U.S. Department of Health and Human Services
• Hexavalent Chromium National Emphasis Program
• Economou-Eliopoulos, Maria; Megremi, Ifigenia; Vasilatos, Charalampos (2011). "Factors controlling the heterogeneous distribution of Cr(VI) in soil, plants and groundwater: Evidence from the Assopos basin, Greece". Chemie der Erde – Geochemistry. 71 (1): 39–52. Bibcode:2011ChEG...71...39E. doi:10.1016/j.che…