A contract that would settle a long-running dispute between Seattle garbage truck drivers and hauling companies Waste Management and Allied Waste is now in doubt due to Waste Management’s refusal to sign it. The hiccup comes three months after the parties reached agreement and has representatives of Teamsters Local 174, which represents the drivers, resuming threats of a strike.

According to a report in the Seattle Times, Waste Management withdrew its support due to complaints from recycling and yard waste drivers represented by Teamsters Local 117, who feel the new contract infringes on their rights. A representative for the company says it will sign the contract once the two Teamsters groups hash things out. For their part, representatives of Local 117 say Waste Management is overstating the dispute and using it as an excuse to stall.

Allied Waste signed a contract with Seattle garbage truck drivers in June.