The online comments were made after a Post-Dispatch article on Sunday said concerns about radiation at the Bridgeton landfill and Coldwater Creek could be overblown, according to experts.

EPA spokesman Curtis Carey said the threats, which have been deleted, were made by one person on the West Lake Landfill Facebook group.

According to the EPA, the comments included: "Let's put these murderers and bribe-takers in the ground." .

EPA, the Agency for Toxic Substances and Disease Registry and the U.S. Army Corps of Engineers all canceled their plans to send representatives to the West Lake Landfill Community Advisory Group's meeting. The volunteer-run group holds these meetings about once a month so residents can ask the agencies questions about the landfill's remaining contamination.

"When they saw the threat, all three agencies said that's not acceptable. It's too great a risk," Carey said.