NORWALK - Norwalk fire and police officials are crediting an anonymous caller for helping them find a stockpile of explosive chemicals.

Investigators say the caller told them about a suspicious odor at 25 Butler St. yesterday afternoon.

Officials say they found hundreds of pounds of combustible chemicals stored in an office space attached to a working machine shop.

Investigators say the man said he was storing the chemicals to make a gasoline additive to improve mileage.