DENMARK — Toxic chemical polychlorinated biphenyls, or PCBs, were found lingering in marine life such as killer whales, according to a new study published in the journal Science.

PCBs were banned in most countries decades ago, however they are still used in some parts of the world, which has allowed them to gradually seep into oceans, according to CNN.

PCBs were used in paints, coolants, carbonless copy paper and other products.

PCBs can be consumed by plankton, which are then eaten by larger fish. As the PCBs move up the food chain, they become more concentrated.

This puts killer whales in danger of consuming highly concentrated PCBs as they are near the top of the food chain.

The chemical was found to disrupt the whales' reproductive system, brain function and the endocrine system.

Mother whales can also pass the deadly chemicals on to their offspring through lactation.

Researchers warn animals living off the coasts of the UK, Brazil, Hawaii, and Japan have a high risk of population collapse because of PCBs.

ORCA, a charity group dedicated to protecting whales, described the report as "an absolute tragic state of affairs and… needs immediate action."