SF fire causes temporary closure of I-280 on- and off-ramps

A fire broke out at a homeless encampment near Interstate 280 early Sunday in San Francisco, causing the closure of some on and off-ramps. A fire broke out at a homeless encampment near Interstate 280 early Sunday in San Francisco, causing the closure of some on and off-ramps. Photo: San Francisco Fire Department / Photo: San Francisco Fire Department / Image 1 of / 5 Caption Close SF fire causes temporary closure of I-280 on- and off-ramps 1 / 5 Back to Gallery

A fire that broke out at a homeless encampment early Sunday temporarily closed some on- and off-ramps on Interstate 280 in San Francisco, authorities said.

No one was injured in the blaze, which was reported just after 6 a.m. and contained by firefighters an hour later. The cause of the fire is under investigation.

The fire impacted Interstate 280’s southbound lanes near the Mariposa Street exit, according to the San Francisco Fire Department. The on- and off-ramps at Mariposa Street were closed to allow for the fire department to access the blaze as crews doused the flames, authorities said.

The ramps were reopened by about 9:30 a.m., according to the California Highway Patrol.

A second fire broke out at a nearby vacant commercial building at 999 Mariposa St., authorities said. There were also no injuries in the second blaze, which was contained.

That fire was accidental and caused by a warming and cooking source, the fire department said.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani