Coastal Raptors is collaborating with Dr. Da Chen, currently a toxicologist at Jinan University in Guangzhou, China. The collaboration started in 2013, when Coastal Raptors sent Da blood plasma samples from six Peregrine Falcons captured that year. Da analyzed the samples for pesticides (DDT and its breakdown products, primarily DDE), PCBs, and fire retardants. While DDT and PCB use has been banned in the US, these chemicals still persist in the environment. Fire retardants called polybrominated diphenyl ethers, or PBDEs, have been added to products such as furniture, electronics and carpeting to reduce the risk of fire-related injuries. PBDEs have emerged as a contaminant threat in recent years.