The Environmental Protection Agency is admitting it was wrong when it issued a report calling for FMC Corp. to stop using a production well as a source for employee drinking water.

But EPA spokeswoman Deborah Flood said Friday all other findings in the report were correct. The report by Seattle-based Ecology and Environment Inc. prompted an EPA investigation into waste operations at the elemental phosphorus plant in southeastern Idaho for possible violations of federal law.The acknowledgment validated claims by FMC officials that the production well in question was not used for drinking water.

"Our report is incorrect," Flood said. "Production well No. 1 was not used for drinking water. Apparently only production well No. 3 is used for drinking water."

The mistake was made, she said, when investigators last year misunderstood FMC officials to say that five production wells at the facility west of Pocatello were used for culinary purposes. A review of the log book revealed that information was erroneous.

The report, which FMC officials have strongly disputed, said unlined waste ponds at the plant were probable causes of contamination of the underground aquifer. Three of six wells tested showed toxic metal levels in excess of federal standards for one or more substances.

The report recommended the unlined ponds be phased out of use and three former waste ponds be properly closed. EPA investigators are looking at the possibility that operations have violated provisions of the federal Clean Water and Safe Drinking Water acts.

The investigation was made to determine whether FMC and the nearby J.R. Simplot Co. fertilizer plant should be added to the national Superfund waste site cleanup list. Neither were added to that priority list.