Originally published by SacBee.com on July 18, 2018

Cal Fire announced Wednesday that charges will be filed against a 17-year-old boy who allegedly caused the Grant Fire with a ‘safe and sane’ firework.

Cal Fire responded to a vegetation fire west of the Grant Line Road exit on eastbound Interstate 580 shortly after 5 p.m. on July 8, according to Sgt. Ray Kelly of the Alameda County Sheriff’s Office. The fire lasted less than 24 hours as fire crews were able to fully contain it by around 7 a.m. the next day.

Kelly said the teen who confessed to sparking the blaze went to the Manteca Police Department on July 9 and told officers he and an 18-year-old friend were driving along I-580 prior to the fire breaking out when they pulled over after having car trouble.

The teen said he was messing around and threw a firework into the engine compartment of the car and it lit the nearby grass on fire. He and his friend tried to put the fire out by stomping it. They left the scene and called 911, but did not disclose that they caused the fire, Kelly said.

The fireworks were marked for legal use, but the use of any fireworks, including ones marked with the “safe and sane” label are illegal in unincorporated areas of Alameda County, Cal Fire said in a press release announcing the cause.

Officers are in the process of submitting charges of “causing a fire in a negligent and reckless manner” to the district attorney’s office and Kelly said the teen will be arrested. Kelly said the charge is different than arson, which is deliberate. The 18-year-old is not being charged.

The fire was thought to have burned more than 640 acres but “enhanced mapping technology” revealed a smaller area had burned. In total, the fire burned 480 acres of the unincorporated state responsibility area.

It took “a large and coordinated response from over a dozen agencies,” including 10 fire and law enforcement agencies, and fire engines from San Joaquin County and the Alameda County Public Works Agency.

“The fire shut down both directions of the highway for several hours and impacted thousands of motorists,” Cal Fire said in the release.

Kelly described the teen, whose name is not being released because he’s a minor, as being “very cooperative and very remorseful.”

“Luckily the fire did not cause any structural damage,” Kelly said.

A version of this story was also published in the print edition of The Sacramento Bee in the local section on page 4B July 20, 2018.