A San Diego Fire-Rescue helicopter drops water. Courtesy SDFD

A wind-driven fire tore across grassy fields and brushy hills near Brown Field airport Thursday, charring hundreds of acres and destroying the stock of a sprawling pallet yard but causing no reported structural damage or injuries.

The blaze erupted for unknown reasons shortly before noon off the 5300 block of Airway Road, near Caliente Avenue in Otay Mesa, according to the San Diego Fire-Rescue Department.

The San Diego Red Cross says a temporary evacuation point has been established at San Ysidro High School, 5353 Airway Road. Red Cross volunteers are en route to assist.

Meanwhile, the region’s air quality agency said residents near the Caliente Fire in Otay Mesa can assume the air is unhealthy for at least sensitive groups.

People are advised to stay indoors to limit exposure to fine particulate matter, according to the Air Pollution Control District of San Diego County. In areas where smoke can be smelled, it’s advisable to limit physical activity.

Ground crews and personnel aboard firefighting aircraft fought the eastward-moving flames, which began spreading just east of San Ysidro High School and burned near rows of apartments just south of state Route 905.

State and federal firefighters were helping city crews extinguish the blaze, said SDFRD spokeswoman Monica Munoz. Ground personnel were aided by four water-dropping helicopters and two air tankers dispensing fire retardant.

In the late afternoon, authorities issued a mandatory evacuation order for areas south of Saint Andrews Avenue, west of La Media Road and east of Cactus Road, most of which are commercial and industrial.

At one of those commercial sites, an industrial yard off Cactus Road, the flames engulfed towering stacks of wooden pallets, causing nearby stored propane tanks to loudly explode and sending a thick column of black smoke into the sky.

As of 6 p.m., the blaze had grown to about 450 acres and was 10 percent contained, Munoz said.

The cause of the fire was unclear.

Updated at 9 p.m. Aug. 1, 2019

— City News Service