Understanding Hexavalent Chromium and Its Industrial Use

Hexavalent chromium (chromium‑6) is a family of chromium compounds in the +6 oxidation state used widely for corrosion resistance, plating, and pigments, and it is recognized as carcinogenic with systemic toxicity (OSHA, 2004; NCI, 2015).

Hexavalent chromium compounds have been used in metal finishing and as corrosion inhibitors because they form protective films that resist rust and wear (OSHA, 2004; TURI, 2019).

Exposure pathways include inhalation of mists and dusts and ingestion through contaminated water, with strongest occupational evidence for increased lung and nasal cancers (NCI, 2015; OSHA, 2004).

At the Hinkley natural‑gas compressor station, PG&E added sodium dichromate (a Cr(VI) compound) to cooling‑tower water as a corrosion inhibitor between 1952 and 1966 (Lahontan Water Board, 2025; Chemistry World, 2017).

The cooling‑tower blowdown (wastewater) containing chromium‑6 was discharged into unlined ponds, from which it percolated into groundwater and created a miles‑long plume (Lahontan Water Board, 2025).

Industrial Contamination and Corporate Deception

Pacific Gas & Electric Company dumped approximately 370 million gallons of hexavalent chromium-contaminated wastewater into unlined ponds at its Hinkley, California facility from 1952 to 1966 (Hinkley Groundwater Remediation Program, 2024).

The contamination occurred despite PG&E's knowledge of chromium-6's toxicity, as company documentation from the 1960s revealed awareness of its carcinogenic properties (Joe Maiellano, 2018).

PG&E failed to notify the California Regional Water Quality Control Board about the contamination until December 7, 1987---over 20 years after dumping ceased and more than 30 years after it began (California Regional Water Quality Control Board, 2008).

The company attempted to destroy incriminating documents, though some records survived to provide crucial evidence for later legal proceedings (UKEssays, 2025).

PG&E used sodium dichromate corrosion inhibitor in cooling water between 1952 and 1966, discharged blowdown to unlined ponds that percolated to groundwater, notified the Board only in 1987, and then approached owners to buy affected properties---actions that limited early public scrutiny and arguably shaped the narrative and exposure footprint (EBSCO Research Starters, 2023; Lester et al., 2022).

The public timeline begins with PG&E's internal discovery and notification on December 7, 1987, when the company told the Lahontan Regional Water Quality Control Board about hexavalent chromium in Hinkley wells, after which orders and cleanup directives were issued (Lester et al., 2022).

Proper Disposal Methods and Historical Costs

Even in mid‑20th‑century practice, best management would have required containing and treating cooling‑tower blowdown rather than discharging to unlined ponds, to prevent percolation to groundwater (Lahontan Water Board, 2025).

Modern standards require wastewater treatment and disposal through permitted systems (e.g., treatment to reduce Cr(VI) to trivalent Cr(III) and precipitate, ion‑exchange, or lined containment with off‑site disposal), rather than unlined percolation (CA DOF/SWRCB SRIA, 2022; TURI, 2019).

Contemporary analyses of hexavalent‑chromium treatment show significant but manageable costs: for small groundwater systems, annualized treatment and disposal can range widely depending on influent concentrations and technology (with weak‑base anion exchange often cheapest at lower concentrations), and disposal of spent media is a key cost driver (CA DOF/SWRCB SRIA, 2022).

National‑scale estimates for meeting a 10µg/L Cr(VI) drinking‑water goal show annualized costs from about $0.55B to $5.1B and capital costs from $3.4B to $28B, indicating that proper treatment is costly but dwarfed by long‑term liabilities when untreated contamination spreads (WQA Journal, 2012).

For the Hinkley station specifically, precise historical counterfactual costs for 1950s--1960s proper treatment are not published; however, orders and program documents make clear that lined containment and treatment would have prevented the miles‑long plume now requiring decades of remediation (Lahontan Water Board, 2025).

In environmental engineering economics, preventing migration from unlined ponds (via lined impoundments and chemical reduction/precipitation or equivalent treatment) generally costs orders of magnitude less than pump‑and‑treat, in‑situ remediation, plume containment, and community compensation sustained over decades (State Water Board, 2020).

These expenditures far exceeded what proper waste disposal would have cost initially, demonstrating the false economy of environmental corner-cutting (Joe Maiellano, 2018).

Government Oversight Failures and Regulatory Responses

The primary government entity PG&E interacted with was the California Regional Water Quality Control Board, Lahontan Region, which issued waste discharge requirements in 1972 prohibiting toxic discharges (Sharon Lester et al., 2022).

Despite these requirements, enforcement proved ineffective due to limited resources and PG&E's withholding of contamination information for decades (Sharon Lester et al., 2022).

Local Hinkley residents lacked the technical expertise and financial resources to effectively confront a major regional utility company about complex environmental contamination issues (Center for Public Integrity, 2022).

State authorities initially failed to pursue the matter aggressively due to limited regulatory frameworks for addressing groundwater contamination and industry influence over regulatory processes (Center for Public Integrity, 2022).

The contamination went largely undetected by authorities because PG&E controlled information flow and residents were unaware of health risks for decades (Center for Public Integrity, 2022).

Yes, the Lahontan Regional Water Quality Control Board issued Waste Discharge Requirements (WDRs) in the 1970s and repeatedly revised them thereafter, many years after the 1952--1966 unlined-pond discharges that seeded the plume (Lahontan Water Board, 2019).

The first WDR for the Hinkley compressor station was adopted on August 10, 1972 (Order 6‑72‑44), with further revisions in 1973, 1974, 1980, 1982, 1990, and later years (Lahontan Water Board, 2019).

PG&E could not legitimately avoid responsibility by saying "we dumped before prohibition," because the Regional Board's 1972 order already forbade toxic discharges (including chromium) harmful to humans or ecosystems and subsequent orders imposed cleanup duties once contamination was identified (Lester et al., 2022).

Moreover, notification in 1987 triggered regulatory cleanup authority, and responsibility for abatement rests with the discharger under California's Porter‑Cologne Water Quality Control Act and the specific WDR enforcement that followed (Lester et al., 2022).

Once notified in 1987 the policy response took the form of cleanup orders but not immediate, broad health surveillance or swift, public-facing risk communication to nearby private well users (Lester et al., 2022).

The "tacit collaboration" critique arises because this combination---late corporate disclosure, property buyouts, and a regulatory focus on containment and long-term technical remedies---left many residents feeling both corporate and state systems failed to protect their health in a timely, transparent manner (Lester et al., 2022).

California established the nation's first drinking water standard for hexavalent chromium at 10 parts per billion in 2014, though this was later invalidated by court order in 2017 and reinstated in 2024 (ASDWA, 2024).

Community Health Impacts and Exposure

Hinkley is a rural Mojave Desert community where many households historically relied on private domestic wells and small groundwater systems for drinking water, which created exposure pathways when the hexavalent chromium plume migrated into the aquifer (Lester et al., 2022).

Policy analyses of the case explicitly note that contamination and exposure persisted "without residents realising it," reflecting reliance on local groundwater sources rather than a large treated surface‑water utility with continuous monitoring and centralized treatment (Lester et al., 2022).

The Lahontan Regional Water Quality Control Board's Hinkley program documents describe a groundwater plume and the need for well sampling and mitigation, underscoring that the primary risk to residents stemmed from well water drawn from the contaminated aquifer (Lahontan Water Board, 2025).

Families in the most contaminated areas were exposed to chromium levels up to hundreds of times higher than background levels, with some wells containing chromium at concentrations far exceeding current safety standards (Center for Public Integrity, 2022).

The health impact assessment remains contentious, with conflicting studies producing different conclusions about cancer rates in Hinkley (Los Angeles Times, 2010).

State epidemiologist John Morgan's 2010 study found 196 cancer cases from 1996-2008 versus 224 expected---slightly fewer than anticipated in the general population (Los Angeles Times, 2010).

However, Morgan's methodology has been criticized for including residents with minimal exposure while excluding those with the highest exposure levels who had already moved away by 1996 (Center for Public Integrity, 2022).

In Morgan's earlier study covering 1988-1993, he found cancer rates 25% higher than expected, but dismissed this as statistically insignificant despite meeting standard epidemiological criteria (Center for Public Integrity, 2022).

Community Destruction and Property Impacts

Property values in Hinkley collapsed as news of contamination spread, making homes unsellable and financially trapping many residents in a contaminated area (Los Angeles Times, 2015).

Public knowledge of contamination spread through media coverage following the 1996 lawsuit settlement and the 2000 film "Erin Brockovich," despite PG&E's attempts at secrecy (Vice, 2015).

PG&E's strategic property buyout program systematically removed evidence of contamination by purchasing and demolishing homes, becoming Hinkley's largest landholder (Raise The Stakes Projects, 2022).

Hinkley's population declined by approximately 85%, transforming a thriving farming community into a near-ghost town as families fled the contaminated area (Next Big Future, 2024).

The local elementary school closed in 2013 due to declining enrollment as families moved away from the contaminated region (Vice, 2015).

Wider public awareness grew in the early 1990s as residents noticed unusual health problems and property buyout offers and as legal clerk Erin Brockovich's inquiry at Masry & Vititoe uncovered medical and water records pointing to chromium-6 contamination, culminating in a 1993 filing (EBSCO Research Starters, 2023).

News coverage intensified around the 1996 settlement and then exploded with the 2000 film "Erin Brockovich," cementing national public knowledge of Hinkley's contamination (EBSCO Research Starters, 2023).

In 2010 PG&E initiated a program to purchase roughly 100 Hinkley properties near the plume boundary, stating an interest in buying affected homes but initially without specific offers disclosed publicly (Los Angeles Times, 2010; UPI, 2010).

Subsequent reporting and community accounts describe PG&E purchasing and demolishing properties as the plume footprint evolved, but public documentation does not consistently disclose the exact formula used (e.g., pre‑stigma fair‑market value versus current market value with stigma) for each transaction (Los Angeles Times, 2010).

Real‑estate stigma research indicates that long‑term environmental contamination can depress property values substantially, and disputes often arise over whether buyout prices reflect pre‑contamination or stigma‑adjusted values, but specific percentage premiums or discounts paid by PG&E in Hinkley are not verifiably published in primary sources (WQA Journal, 2012).

Based on available contemporaneous coverage, a definitive conclusion that PG&E systematically paid "fair" (pre‑stigma) prices cannot be made without access to transaction‑level appraisals and contracts; the public record confirms intent to buy affected parcels but not uniform valuation methodology (Los Angeles Times, 2010).

Hinkley's pre‑disclosure population is not precisely fixed in one public source, but contemporaneous accounts describe it as a small Mojave Desert community with on the order of a few thousand residents prior to the 1990s contamination publicity, shrinking significantly in the years after settlement and later plume expansions (ABC News, 2021; Lester et al., 2022).

The policy literature frames Hinkley as a case where contamination and exposure persisted for years "without residents realising it," with a formal policy response beginning three weeks after PG&E's 1987 notification (Lester et al., 2022).

Legal Resolution and Financial Consequences

The 1996 lawsuit (Anderson et al. v. PG&E) was brought by Hinkley residents represented by the Masry & Vititoe law firm, catalyzed by Erin Brockovich's discovery of irregular medical records and the firm's investigation into chromium‑6 in local wells (EBSCO Research Starters, 2023).

Residents learned of the problem through a combination of PG&E's 1987 notifications to the regional board, word-of-mouth after conspicuously high property-buyout offers, and the law firm's outreach and record-gathering prior to filing in 1993 (EBSCO Research Starters, 2023).

The 1996 class-action settlement of $333 million represented the largest direct-action lawsuit settlement in U.S. history at that time, involving approximately 650 plaintiffs (Salon.com, 2000).

Erin Brockovich, working as a legal clerk, played a crucial role in organizing residents and gathering evidence against PG&E, though her portrayal in media has been criticized by some residents (Sharon Lester et al., 2022).

The case was resolved through arbitration rather than trial, avoiding public disclosure of many potentially damaging internal corporate documents (Joe Maiellano, 2018).

PG&E's total costs related to Hinkley contamination have exceeded $900 million, including the initial $333 million settlement, an additional $295 million settlement in 2006, $20 million in 2008, ongoing cleanup costs, and legal fees (San Bernardino County Sentinel, 2013).

The company has spent nearly $100 million on cleanup efforts that are projected to continue for over 100 years, with some estimates suggesting 150 years for complete remediation (Raise The Stakes Projects, 2022).

No PG&E executives faced criminal charges related to the environmental contamination, despite decades of documented corporate deception (Wikipedia contributors, 2004).

Ratepayers have shouldered significant portions of PG&E's environmental liabilities through rate increases, though specific percentages for Hinkley costs are not publicly disclosed due to settlement confidentiality agreements (GVWire, 2024).

Total environmental remediation costs are projected to exceed hundreds of millions of dollars over a cleanup period estimated at 150+ years (Raise The Stakes Projects, 2022).

Critical Perspectives on Corporate Environmental Responsibility

Environmental activist Erin Brockovich condemned corporate environmental irresponsibility, stating: "Dr. Seuss wrote The Lorax out of anger about what he saw as corporate greed ruining our natural world" (Erin Brockovich, 2021).

Former Hinkley resident Roberta Walker expressed ongoing frustration: "The water crisis is still going on, and it's not going to be taken care of in our lifetime... I don't think it's ever going to end" (Environmental Health News, 2024).

Critics characterized PG&E's actions as emblematic of broader corporate environmental irresponsibility, with one analysis noting: "The company had put profits above public health. PG&E had the resources, the technology, and the manpower to clean up its own mess and yet chose to lie, cheat, sue, intimidate, falsify documents, and outright bully anyone trying to protect the rights of water-drinking consumers" (PMC, 2021).

Brockovich has emphasized the systemic nature of environmental injustice, writing that her work exposes "the negligence and greed of those in power who prioritize short-term profits over the long-term health and well-being of people and the environment" (Bookey, 2023).

Environmental justice advocates have criticized the broader failure of authorities, with Brockovich stating: "People who contact me share my feelings of frustration. They see the devastation firsthand, knowing there's been a breakdown in the regulations meant to protect them. Many have reached out to their local officials to no avail" (Erin Brockovich, 2021).

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