The head of the mid-Atlantic region of the Environmental Protection Agency has been dismissed because of a conflict with EPA Administrator Carol Browner, the agency said.

EPA spokesman David Cohen said that Peter Kostmayer, a former Pennsylvania congressman, would leave his post as administrator of the EPA's Region III on June 1.

The region's headquarters is in Philadelphia. It covers Pennsylvania, Maryland, Delaware, West Virginia, Virginia and the District of Columbia.

Environmentalists accused Browner of forcing the dismissal because of Kostmayer's aggressive scrutiny of a proposed $1 billion pulp and paper mill being planned in West Virginia and a proposed four-lane highway between Elkins, W.Va., and Strasburg, Va.

Kostmayer had said there has been pressure for his dismissal from Democratic Sens. Robert C. Byrd and Jay Rockefeller, both of West Virginia, and West Virginia Gov. Gaston Caperton.

Caperton, a Democrat, said that he had nothing to do with deciding who has the job, but acknowledged that he told Browner that "we did not feel people (in the region) were playing by the rules and following regulations."

Kostmayer also has come under sharp criticism from Virginia Gov. George Allen, a Republican, who has accused the EPA of imposing unnecessarily costly clean air requirements on his state.

Several days before the announcement, the Charleston (W.Va.) Daily Mail quoted Browner as acknowledging a rift with Kostmayer. "It's a disagreement over how to work with people. It would be best if he looked for opportunities outside the agency."

A senior EPA official, speaking on the condition he not be named, said the decision was made because of "numerous complaints about Mr. Kostmayer's managerial style from both EPA staff and many citizens and organizations outside of EPA."

Stanley L. Laskowski, deputy administrator in the Philadelphia office, will become acting chief when Kostmayer leaves, officials said.