Cancer-causing substances have been discovered in the waters and air of the Gulf of Mexico near the BP oil spill area, at levels much greater than before the spill occurred, according to researchers from Oregon State University.

Increased levels of polycyclic aromatic hydrocarbons, or PAHs—some of which are known carcinogens—were found along the coastlines of Mississippi, Alabama and Florida, but the greatest increase was off Louisiana, where levels measured 40-times greater than before the spill. Ominously, the substances are available to be taken into the food chain.

The measurements were recorded in May and June, during the height of the BP oil spill, when hundreds of thousands of gallons of oil gushed into the Gulf each day. New measurements are now being taken to see if degradation of the PAHs is taking place.