MIDDLETOWN, Ohio (AP) — An environmental group has released a study it says links pollution in a creek to AK Steel, a contention the company refutes in a study it commissioned.

The Sierra Club, which released its report Thursday, is one of four organizations — along with the U.S. and Ohio Environmental Protection agencies — that have sued AK Steel, claiming the company allowed PCB-laced fluids to leach out of its landfills and into Dick’s Creek.

Alan McCoy, spokesman for AK Steel, said the Sierra Club’s tests don’t prove anything. The company’s consultant produced a report stating there are dozens of other companies and plants along the creek that could have caused the pollution.

The Sierra Club says testing it commissioned shows that PCBs taken from two sites in the creek match chemically with PCBs found in the steel mill’s landfill.

PCBs, or polychlorinated biphenyls, were once widely used as insulating material and are believed to cause cancer.

“The report compares our two samples to each other. They have very similar patterns of concentrations, indicating they are from the same source,” said Susan Knight, water sentinels project director for the Sierra Club.

More complicated testing and analysis still has to be performed before the results are complete enough to be incorporated into the lawsuit, she said.

Ohio EPA spokeswoman Heather Lauer questioned whether the sampling is large enough for a definitive link to AK Steel.

“Two samples — that’s a pretty limited number,” Lauer said.

She said the agency was not ready to draw conclusions from the samples.

“I don’t believe you will find anyone in the scientific community that would be able to make any conclusion based on two data points,” McCoy said.