Waste Management says a new study released Thursday shows PCB compounds are being well managed at the company's toxic landfill near Kettleman City---meaning the landfill is not a significant threat to human health.

Some people in that Central Valley town suspect PCBs are responsible for a birth defect cluster there.

The U.S. Environmental Protection Agency asked Waste Management to conduct the study in December of 2008. As Waste Management's Brian Bowen explains, the company believes the findings should ease doubts in Kettleman City.

"It seemed to support our belief that there is no offsite migration of PCBs from the facility," says Bowen.  

Bowen says the study suggests PCBs could not have spurred birth defects four miles away in Kettleman City.

However the mothers of children born with defects have retained lawyers in the case. Those lawyers have hired scientists who are conducting their own investigations. 

The study is also important to Waste Management's plans to expand their landfill. Any expansion would require new permits   from the U.S. EPA.  

The EPA did not return requests for comment on the study. The agency did post a statement on its website.

"Based on the study findings PCBs… are not migrating off site….," The statement reads in part. "EPA's position remains that we will not issue a permit to CWM [Waste Management] unless we are confident that the facility does not present a health risk to the community."