WASHINGTON --- Trade-ins from the Cash for Clunkers program are piling up and auto recyclers are seeking more time to meet the deadline for disposing of all those vehicles.

At some places, Ford Explorers, Chevy Blazers, Chrysler Town & Country minivans and other clunkers are parked bumper to bumper on several acres, many marked "C4C" on their windows, waiting to be drained of fluids, stripped of valuable parts and flattened for scrap.

"I've got a parking lot of almost 4,000 vehicles right now," said Harry Haluptzok, the chief executive of John's Auto Parts in Blaine, Minn., near Minneapolis. His business typically dismantles 100 vehicles per week, but the workload has now more than doubled, and Mr. Haluptzok hired 10 more workers to keep up with all the extra vehicles.

Under the program, the cars are required to be crushed or shredded within six months of the date the vehicle is transferred from the dealership. Recyclers say the deadline, even a few months away, will be hard as they try to remove spare parts such as transmissions, front and rear axles, starters and alternators.

Consumers bought nearly 700,000 new vehicles in late July and August through the program, taking advantage of rebates of up to $4,500 on new cars in return for trading in their older vehicles. Congress tripled the size of its original $1 billion price tag because of the program's popularity.

The American Recyclers Association, a trade group representing auto recyclers, said the six-month deadline was developed in line with the initial $1 billion program, but never took into account the additional vehicles sold when the program was expanded.

Transportation Department spokeswoman Sasha Johnson said the department was aware of the request and noted that under the regulations, "most trade-ins through the CARS program do not need to be crushed until at least early next year."