Chrome-Plated Fraud

How PG&E's Scientists-For-Hire Reversed Findings of Cancer Study

December 23, 2005

Chrome-Plated Fraud: Debate Over Chromium Standards

Chromium is a naturally occurring metal used in steel manufacturing, leather tanning, welding, and the production of dyes, pigments and alloys. It is also often used to plate metal surfaces, is a major component of the pesticides used in pressure-treated lumber, and was also a common anti-corrosive agent used in cooling towers until the federal government banned the practice in 1990. [15] But not all chromium is created equal.

Trivalent chromium, or chromium-3, is a necessary nutrient naturally present in many foods and added to many vitamins as a dietary supplement. The other major type, chromium-6, is produced mainly through industrial processes, enters living cells much more readily than trivalent chromium, and is known to cause a variety of acute health effects when ingested at high levels, including vomiting, convulsions, ulcers, kidney and liver damage. [15,16]


There is no question that chromium-6 is a dangerous chemical. The International Agency for Research on Cancer, the EPA, and the National Toxicology Program all say chromium-6 causes cancer when inhaled. [16,17,18] Last year the Occupational Safety and Health Administration (OSHA) announced it would lower its safety standard for inhaled hexavalent chromium by a factor of more than 50 after it became clear that the current standard was too high to protect workers. [19]

How dangerous chromium is in drinking water is more controversial. Scientists agree that much chromium-6 is converted to the safer chromium-3 by stomach acid. But how quickly, and how much? Once inside a cell, chromium-6 is extremely toxic. If cells take up chromium-6 before it converts to chromium-3, it has the potential to cause many health problems, including cancer. Recent research has shown that orally ingested chromium-6 penetrates to tissues and organs throughout the body. [20]

In 1977, California set a safety standard of 50 parts per billion (ppb) for total chromium (which includes all chromium compounds) in drinking water. The EPA subsequently adopted the same standard, then in 1991 weakened it to 100 ppb. California disagreed with the looser standard and retained its original 50 ppb limit, the same guideline used by the World Health Organization. [21,22]

But in the late 1990s the California Environmental Protection Agency (Cal-EPA) realized that even this level was still too high to adequately protect human health and began to re-examine the standard. [14,21] In 2001 the state Legislature passed a law requiring the Department of Health Services (DHS) to set a drinking water standard just for chromium-6. [14] The standard is more than a year overdue, but when it is set California will be the first state to specifically regulate chromium-6 in drinking water.

To set a standard, the first step was for OEHHA to determine the level of chromium-6 in water that would be safe for all Californians to ingest over the course of a lifetime with no adverse effects. To establish this Public Health Goal (PHG), OEHHA reviewed all available toxicity information, including the 1997 JOEM article. The paper was important because it was the only drinking water study in the scientific literature to report on specific types of cancer. [9] Second, the panel of scientists assigned by the University of California — including Paustenbach — to provide OEHHA guidance had given the study great emphasis. [12] OEHHA wasn't looking for a scientific fraud or a polluter's coverup — but that's exactly what it found.