Officials believe electrical shorts might be causing manhole explosions in New Jersey.

Manhole covers in Atlantic City blew in the air for the third straight day Tuesday. No one has been injured.

Firefighters say the five manholes that have exploded contained electrical equipment.

Fire Chief Dennis Brooks tells The Press of Atlantic City he saw a 200-pound cover shoot 10 feet in the air trailed by a yellowish-orange arc of electricity.

He says there was a deafening boom created by electricity "displacing the air in a confined space. Bam! It blows the top off."

Brooks says an electrical short from an underground utility box apparently caused the arc.

A spokesman says Atlantic City Electric is working to restore power.