WASHINGTON - Workhorse Custom Chassis, a Navistar company, is recalling 521 MY 2010 W42, W62 and MY 2011 W22 Workhorse trucks built with a General Motors gasoline engine and equipped with a Remy alternator. 

The recall was prompted because a low-resistance electrical short in the alternator's voltage regulator may occur, according to the National Highway Traffic Safety Administration. This poses a fire risk. 

Dealers will inspect and replace the alternator if necessary free of charge. The recall will get underway in May. 

Owners can reach Workhorse at (877) 246-7731.