NEW YORK — New York fire officials say a resident in a Chinatown building set off two rounds of bug bombs to battle an infestation, causing an explosion that injured 12 people.

Fire officials say the woman set off 20 canisters Wednesday. On Thursday, she deployed about two dozen more but forgot to turn off a pilot light. The poisonous flammable fumes exploded, shattering windows on three floors. Three people were seriously hurt.

Bug bombs are also known as foggers. The U.S. Environmental Protection Agency issued new warning labels last year reminding people to not use more than one in a room at a time and to turn off all electronic appliances and pilot lights because the pesticides are highly flammable. They cause about 500 explosions annually nationwide.

The fire was considered accidental.