Environmental advocates filed a lawsuit in San Francisco Tuesday against five companies who make fish oil supplements, along with retail stores that sell them, claiming the supplements contain levels of polychlorinated biphenyl compounds at levels above what has been deemed safe by health regulators. According to the lawsuit, tests done on fish oil products found levels of PBCs that exceed the California daily limit by a factor of 10 in terms of cancer risk. PCBs were banned by Congress in 1979 as they were know to cause cancer and birth defects. The lawsuit is asking for a label to be put on the products warning consumers of the risks.