Toxic oil is toxic.

PhysOrg has bad news for the Gulf of Mexico. Oil spills are even more toxic than we thought:

The study, spearheaded by the UC Davis Bodega Marine Laboratory in collaboration with NOAA, looked into the aftermath of the 2007 Cusco Busan spill, when that tanker hit the San Francisco-Oakland Bay Bridge and spilled 54,000 gallons of bunker fuel into the bay.

The key finding involved the embryos of Pacific herring that spawn in the bay. The fish embryos absorbed the oil and then, when exposed to UV rays in sunlight, physically disintegrated. This is called phototoxicity, and has not previously been taken into account when talking about oil spills.

“This phenomenon had been observed in the laboratory, but had never been observed in the field, and there were even some skeptics out there wondering if this was just a phenomenon that people would see under lab conditions,” said Gary Cherr, director of the marine lab and professor of environmental toxicology.