BIDDEFORD – Mounting frustration over contract problems involving police and public works employees came to a head when Mayor Donna Dion expelled about 40 unruly union protesters from the City Council chamber.

The Tuesday night meeting ended moments later, after a councilor who has supported the union slumped in his chair complaining of chest pains and was rushed to Southern Maine Medical Center.

Dion and several councilors followed Councilor Philip Castora to the hospital, where he was admitted for observation of a chronic heart condition.

The city’s police and public work employees have been working without a contract since July in a dispute that centers around the city’s attempt to require its union employees to pay more for health benefits.

In March, the city’s police chief warned city workers not to disrupt council meetings by honking horns outside. Instead, members of Teamsters Local 340 have made their feelings known by packing City Council meetings in a silent protest against the city’s stance.