Higher than normal levels of potassium were noted at one of the nearly two-dozen monitoring wells at the Warren County site, Ohio Environmental Protection Agency records show. That well was already on a watch list, but this is the first time a well at the landfill site has been elevated to the corrective measures stage, EPA district geologist Steve Lowry said.

Browning-Ferris is expected to respond within a couple of months, he said.

"It appears that the landfill is impacting the groundwater," Lowry said. "From a public health standpoint, it could be a whole lot worse than this. ... It's not the nasties you'd think about when you think about groundwater being impacted by a industrial-type facility."

Potassium, sodium and chloride are naturally found in groundwater, he said, but recently recorded levels are higher than this well's usual readings. Officials do not think it is a serious health threat.

A report from Missouri-based Herst & Associates Inc, sent to the EPA in August on Browning-Ferris' behalf, maintains the levels are the result of natural variations in the site. The report states: "There is no indication, based on a review of the available data from these wells, that leachate from the landfill has impacted groundwater quality."

"With a sanitary landfill, there are always environmental issues," said BFI's attorney C. Francis Barrett. "... Every time any issue's been brought to BFI's attention, it has been satisfactorily addressed."

Bigfoot Run operated until May 1999, when it was closed and topped with about 4 feet of clay and vegetation layers. Regulations require environmental monitoring for 30 years after a landfill is capped. Groundwater tests are done every six months.

The test that detected the potassium was done in March and submitted to the state in May. In August, Browning-Ferris submitted its explanation of unusual well readings and the state had until this week to make its own evaluation.

The landfill site has been a source of contention since it closed because Browning-Ferris wants to build a second landfill near the same site. Residents and the county don't want it.

Resident George Agricola said his primary concern is the nearby Little Miami aquifer.

"It's the water system for a lot of folks in the Morrow area," he said.

The well in question is not near the aquifer, so experts do not believe any contamination has occurred there. Other wells are also being assessed.

"We had no reason to believe that this was leaking," Warren County Commissioner Pat South said. "I don't care if it's considered a small leak at this point. Small leaks grow. That is naturally the fear of anyone."

E-mail esolvig@enquirer.com