BIDDEFORD – The police chief is warning horn-tooting city workers to put a lid on their noisy protests outside City Hall.

Councilors complained that honking during a meeting this week made it difficult to conduct business, so Police Chief Roger Beaupre issued a memo warning that “prolonged horn tooting” could result in criminal charges.

“I don’t know how many people were tooting their horns,” Beaupre said Thursday. “But it could have been 10 or 15, and it lasted maybe for 10 or 15 seconds, but that can be an eternity if you’re trying to conduct business.”

Biddeford’s teachers, police and public works employees have been working without contracts since July and no settlements are expected soon. The employees have conducted several protests, including crowding City Council meetings and informational pickets.

The dispute focuses on the city’s attempt to require its union employees to pay more for health benefits. Biddeford faces a $1.7 million increase in medical insurance costs over the next three years.

Steve Roscia, a public-works union spokesman, said he considers the horn blowing a protected right of free speech.

Roscia said he wasn’t among those honking their horns Tuesday night during the meeting. But he said he has done so on previous occasions outside council meetings. “It’s never been an issue until now,” he said.

Terry Davis, spokesman for the police union, said the chief’s memo will be referred to the union’s lawyers.

Beyond that, Davis declined comment. “When we get threatened for our jobs, I am going to be very careful what I say,” he said.

Brian MacMaster, director of investigations for the state attorney general’s office, said using horns to “intentionally or recklessly annoy” people represents criminal conduct, as opposed to the use of horns to celebrate after a football game or some similar public event.

He said a police officer could lose his state certification if convicted of charges stemming from the horn blowing.