Three years after 21 firefighters were injured in a fire at an Oceanside dry cleaner, an explosion in the same building shook the neighborhood Thursday.

Officials say an explosion powered the boiler through the back wall of the Oceanside Industrial Industries building on Long Beach Road. They say the boiler, which is eight feet in diameter, caused significant structural damage to the building. While the cause of the explosion remains unknown, fire officials say the seven or eight workers who were in the building are lucky to have escaped without injury.

According to the fire department, steam and high-pressure gas both leaked from the building. KeySpan workers arrived at the scene to shut off the gas. They say the gas leak did not affect any residents.