SAN CARLOS (CBS SF) – Firefighters responded to a 1.5 acre grass fire at Arguello Park, in San Carlos Monday night.

The fire broke out around 9:35 p.m. at the park, located at 260 block of Wellington Drive, according to the San Mateo County Fire Department.

No structures were threatened and there were no reports of injuries

Firefighters tweeted they would remain on the scene for several hours “mopping up.”

The cause of the brush fire is under investigation.