PITTSBURGH — The union representing nearly 14,000 Goodyear Tire & Rubber workers at 12 U.S. plants is threatening to call employees to the streets this Thursday.

The United Steelworkers of America says it will cancel its labor contract and strike in three days if a new agreement isn’t reached with the company, reports Associated Press.

Goodyear, the largest U.S. tire maker and a major provider to the trucking industry, says negotiations continue with the union over a new contract, but the company has contingency plans in place if a mutual agreement isn’t reached in time.

The two sides have been negotiating since June 9 and operating under daily contract extensions since July 22. That agreement included a provision that either party could terminate the deal with 72-hour notice.

The 12 plants that would be affected include both automotive and commercial vehicle production.

Truck OEMs eagerly await a solution to the stalemate. Supply lines have already been tight as tire makers cope with raw material cost increases and a demand for specialized equipment. There’s been some reported shortages in the commercial vehicle sector over the last couple years, leading some truckmakers to limit their exposure to a single supplier.

Transportation market analysts Bear Stearns in New York suggests that class 8 production may slow if a supply chain disruption ensues, but OEMs should be able to continue assembling pre-bought trucks using “placeholder” tires. If there’s an extended strike, retreading suppliers might see some modest benefit, says the firm.

Meanwhile, Goodyear rival Bridgestone Firestone could be facing a similar showdown with the same union, as the two sides are also in the middle of tense negotiations.

The United Steelworkers union has indicated it wants to settle things with Goodyear before addressing the Bridgestone Firestone contracts.

— with files from Associate Press