PCBs are known to cause a variety of types of cancer in rats, mice, and other study animals. Once PCBs have entered the body through ingestion, inhalation or direct contact, they can act as endocrine disrupters and neurotoxins.

Why just "probable carcinogens"?
The classification should not be seen as just a small chance of danger in humans as carcinogens. The "probable" in EPA's regulations simply says that it is known to cause cancer and there is evidence that suggest that is causes cancer in humans but isn't conclusive. The main reason that it is not conclusive because researchers cannot simply expose humans to a dangerous chemical as part of a study. Instead they must rely on small groups of people known to be exposed to the chemicals. Because of this and other limitations in human studies, carcinogens are rarely classified as "known."

New York State's fishing and fishing consumption advisories have stated that "Women of childbearing age, infants and children under the age of 15 should not eat any fish species from any reach of the Hudson River."

A differing view point
According to General Electric's website hudsonvoice.com, "more than 100 human health studies have found no evidence that PCBs cause cancer or other serious illnesses in people. The U.S. Environmental Protection Agency regulates PCBs as "probable human carcinogens" based on studies in which rats were fed very high doses of PCBs in their diets." Is it true that they don't cause cancer or serious illness in people? The truth isn't really known, and may never be known, as it is hard to do accurate human studies based on the nature of PCBs.

The EPA's latest assessment of the river and PCBs has determined that the river is safe for swimming, wading, boating, and possibly a treated drinking water source. According to GE, "the risk PCBs pose is to people who eat large amounts of Hudson River fish each week for 40 years." in its latest assessment of risk associated with PCBs in the Upper Hudson, EPA has determined the Hudson River is safe for swimming, wading,