Retired Chicago police officers will be getting letters in the mail soon saying the city won’t certify them to carry guns—a move that angers the head of the local Fraternal Order of Police, according to The Chicago Sun-Times.

Congress passed the Law Enforcement Officers Safety Act of 2004 to allow retired and off-duty officers across the country to carry concealed firearms.

But Chicago claims it is worried about the liability of allowing retired cops to carry guns when they haven’t gone through refresher training or undergone mental and physical fitness evaluations. The city also is concerned about the lack of a national database of retired officers authorized to carry guns.

Sheri Mecklenburg, counsel to police Supt. Phil Cline, said the federal law does not define how a department should determine an officer had retired “in good standing.”

The letter to retired Chicago cops says “until these areas of concern are addressed by federal legislation, the Department has declined to adopt new procedures for qualifying retired officers to carry a firearm.”

Under the city’s interpretation of the federal law, the city can’t bar out-of-town certified retired officers from carrying guns.