Recycling and yard waste drivers for Waste Management went on strike Wednesday morning, accusing the company of bargaining in bad faith during ongoing contract negotiations.

Picket lines went up at 10 a.m. as drivers in King and Snohomish counties went on strike. The action by Teamsters Local 117 is expected to disrupt services to area residents; the extent of that disruption was not immediately clear.

At issue in the stalled contract negotiations -- according to the Teamsters -- is a pay disparity between recycling drivers and their garbage-hauling counterparts. According to the union, garbage haulers earn $9 more an hour than recycling drivers.

In a statement, Teamsters leaders faulted Waste Management for what they described as violations of federal labor law. They claim the company has been coercing and direct dealing with its employees, threatening workers and unilaterally changing working conditions.

"Waste Management has forced this labor dispute through its blatant disregard of U.S. law," Local 117 Secretary-Treasurer Tracey A. Thompson said in a statement. "Now they are on the verge of provoking a public health crisis..."

"We call on Waste Management to return to the bargaining table immediately and bargain a fair contract in good faith that recognizes the health and safety hazards its drivers face on the job."

According to the Teamsters, 153 recycle and yard waste drivers employed by Waste Management have been working without a contract since May 31. On June 2, the drivers unanimously voted to authorize a strike.

In June, Teamsters members ratified a contract with another waste handler, Allied Waste/Republic, after the company agreed to address the apparent disparity, according to a Teamsters statement. Describing the negotiations as "challenging," a union spokesperson asserted the Allied Waste/Republic drivers overwhelmingly ratified a contract after the pay dispute was resolved.