An explosion at an industrial park in Valencia sparked a brush fire and sent at least four people to the hospital Tuesday afternoon, officials said.

The incident was initially believed to have occurred at a movie set, but officials later described it as an industrial accident involving a private business.

Crews responded to initial reports of a possible explosion on the 25100 block of Rye Canyon Loop just before 4:45 p.m., according to the Los Angeles County Fire Department.

Firefighters arrived at the scene just before 5 p.m. and reported a quarter-acre brush fire creeping uphill, officials said.

Crews managed to stop the forward progress of the blaze, dubbed the Rye Fire due to its proximity to Rye Canyon Loop, around 5:20 p.m. after it grew to an acre, the Fire Department said in a tweet.

Fire officials reported that three people with “critical burns” were transported to a local hospital. A fourth victim drove themself to a local emergency room.

Aerial video from Sky5 showed the blaze occurred near a storage site. Officials later said the incident was an accident involving a private business within the Southern California Innovation Park, and not a movie set.

The Santa Clarita Valley Sheriff’s Station also confirmed later that no filming had been taking place when the explosion occurred.

Fire crews and a hazardous materials team were investigating the incident, the Sheriff’s Station said in a tweet.

No homes were threatened and no evacuations had been ordered.