About 25 Mount Vernon firefighters battled a fire at a building Monday.

Employees of a die casting shop tell News 12 that the fire sparked right above their heads, and that the four people inside were forced out as the smoke built up on top of the building.

Workers at Crown Die Casting, located on West Lincoln Avenue, say they melt metal inside. It's already extremely hot, and the equipment inside someone erupted in flames.

"The furnace gets very hot, and the temperature caused the fire. After that, we just got out," said employee Andrew Clark.

The smoke was so heavy that it seeped into vents and poured into the Franciscan Mission right next door. The brother there told News 12 that he sent the 38 employees there home early because of the smoke.

No one was hurt as a result of the fire.

The exact cause of the fire remains under investigation.