NEW CASTLE — Massachusetts has pulled the fireworks license from a New Castle firm after several leftover, unexploded fireworks shells were detonated when they were hit by riding lawnmowers.

Massachusetts Fire Marshal Stephen Coan says the shells were left over from July 4th displays produced by Pyrotechnico.

Nobody was hurt because the heavy commercial mowers shielded workers from the blasts.

Coan says mowers hit shells that exploded in the towns of Ware, Waltham and Stoughton several days after shows in those towns. Live leftover shells were also found in two other Massachusetts towns.

Pyrotechnico is blaming the problem on defective fireworks from China, but company president Steve Vitale also believes Massachusetts officials are blowing the story out of proportion.