DEFIANCE -- General Motors Co. will lay off 135 employees from its Defiance Casting plant, the automaker confirmed today.

A company spokesman said the shift toward fuel-efficient engine technologies has reduced demand for iron casted engine components. 

"GM is committed to the delivery of top quality, fuel efficient engines and components for our customers," the company said in a statement. "To enable this, the product mix of our newer engines has more aluminum content."

GM said 48 of the 135 employees who will be laid off were temporary employees whose assignment will end at the end of September. The remainder of employees include 55 regular permanent employees and 32 skilled trade employees. 

A phased layoff plan will be in place by the end of September and will be finished by the end of the year.

As of June, the plant employed about 1,300 people. Of those, 1,129 are hourly employees.

The plant makes cylinder blocks, cylinder heads, and crankshafts.

First Published August 29, 2013, 7:31 p.m.