WASHINGTON — The Environmental Protection Agency is telling its pollution enforcement officials not to talk with congressional investigators, reporters, and even the agency’s own inspector general, according to an internal e-mail provided to the Associated Press.

The June 16 message instructs 11 managers in the EPA’s Office of Enforcement and Compliance Assurance, the branch of the agency charged with making sure environmental laws are followed, to remind their staff members to keep quiet.

“If you are contacted directly by the IG’s office or GAO requesting information of any kind … please do not respond to questions or make any statements,” reads the e-mail sent by the division’s chief of staff, Robbi Farrell. Instead, staff members should forward inquiries to a designated EPA representative, the memo says.

Public Employees for Environmental Responsibility obtained the e-mail and provided it to the AP. The group is a nonprofit alliance of local, state, and federal professionals. Its Web site carries the slogan, “Protecting Employees Who Protect Our Environment.”

Its executive director, Jeff Ruch, said yesterday the e-mail reinforces a “bunker mentality” within EPA under the Bush administration.

“The clear intention behind this move is to chill the cubicles by suppressing any uncontrolled information,” Mr. Ruch said.

The EPA, in an official statement, said yesterday the e-mail was aimed at making agency responses to the press, EPA’s inspector general, and Congress’s General Accountability Office more efficient, consistent, and coordinated. The EPA also said officials could still talk to investigators as long as they checked in with the appropriate representatives. About 900 lawyers and technical support staff are employed by the division at EPA headquarters in Washington.