Updated

Police arrested four teenagers Thursday after they allegedly sparked the Gilroy Ballybunion Fire in northern California while playing with illegal fireworks during Labor Day Weekend.

The teens, aged 14 and 15, were seen using “firecrackers” Sunday night in Gilroy, according to police, when flames broke out on the hillside. Police said the teens tried to extinguish the blaze but it soon spread out of control, The Mercury News reported.

The Ballybunion Fire, which grew to 100-acres in Gilroy, was deemed 100% contained Thursday afternoon, according to Cal Fire’s incident report. No homes or structures were damaged, but one firefighter was briefly hospitalized after losing his footing and falling 40 feet. Firefighters are expected to remain on the scene for a few days for “fire line repair.”

Police interviewed the teens and arrested them for unlawfully causing a fire on forest land -- a felony offense punishable by a fine or imprisonment for up to three years.

The parents of the teens took custody of them after they were released.