Killer Whales (Orcas) (IMAGE) American Chemical Society Caption Exposure to toxic PCBs poses a long-term threat to orcas, also known as killer whales. Credit Courtesy of National Oceanic & Atmospheric Administration Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.