A quiet labor union demonstration Tuesday before Sonoma County supervisors turned unexpectedly loud when balloons brought in as props by union members burst during the meeting.

The disturbance involved several dozen members of the county's largest labor union, SEIU Local 1021, who had gathered in the board chambers to protest ongoing contract talks.

Carrying purple balloons emblazoned with the word "Enough," union members took their seats quietly during a board presentation on county parks. As the meeting progressed, union members released more than two dozen balloons, which rose to rest on the room's 20-foot ceiling.

Several popped when they touched the light fixtures, startling members of the audience. The noise prompted board Chairwoman Shirlee Zane to interrupt the hearing and issue an unusual request: hold onto your balloons.

"The heat is going to make them pop," she said. "Be respectful that we have other agenda items and presentations."

After the meeting ended, Russell Mortensen, a county building mechanic, retrieved the balloons.

An SEIU Local 1021 representative could not be reached hours later for comment on the protest.