Two people were taken to the hospital and their dog died after a fire broke out inside their apartment on Highland Avenue in San Mateo in the early hours of Friday, Oct. 9.

The San Mateo Consolidated Fire Department was called at about 2:20 a.m. to 839 Highland Ave., a two-story, six-unit building just south of the Burlingame city line, the San Mateo Daily Journal reported. The fire went to two alarms, and the response included a Level 1 mass casualty incident activation, a plan fire agencies use to organize care for injured people while crews fight the flames.

One unit damaged, residents displaced

According to the Daily Journal and Hoodline, the fire stayed in a single apartment, and the two people hospitalized lived in that unit along with the dog that was killed. No one else was reported hurt, and the other five units were not affected. Hoodline reported that crews had the fire out in under half an hour.

Heat, smoke and water left the burned apartment unlivable, so its residents are displaced for now. Officials have not said how the fire started, and the cause remains under investigation. The condition of the two people taken to the hospital has not been released.

About the building and the department

The building dates to 1970 and sits in North Central San Mateo, one of the city's densest areas for apartments and other rentals, Hoodline noted, citing property records that show it sold in 2024 for $3.35 million.

The San Mateo Consolidated Fire Department has served San Mateo, Foster City and Belmont since the three cities merged their fire agencies in 2019. Its stated goal is to reach 90% of top-priority emergency calls in under seven minutes.

A reminder for renters

Overnight fires are especially dangerous because people are asleep when they start. Fire officials across the Bay Area routinely urge renters to make sure each bedroom area has a working smoke alarm, to know two ways out of their unit, and to carry renters insurance, which can cover temporary housing if a fire forces them out.

Bay Area Brief will update this story if investigators announce a cause or share more on the residents' condition.