Investigators are looking into whether Friday's 13-acre brush fire near Interstate 8, just south of Los Coches Road in El Cajon, was intentionally set.
According to the California Highway Patrol (CHP), a witness reported seeing a man leaving the area just before the fire sparked around 4 p.m. Friday.
NBC 7's News Chopper video showed flames and smoke above the area.
A Sig Alert was issued for both directions of Interstate 8 for the afternoon, CHP officials said.
The fire came close to a Walmart in the shopping center on Los Coches Road.
Kathy Miles was shopping there at the time when she saw the smoke and flames.
"The smoke was so thick, it was really gray out here, and the sky was turning orange," Miles said.
Heartland Fire helicopters made several water drops on the fire.
Cal Fire and Heartland Fire crews staged on the eastbound shoulder of the freeway and behind the Walmart.
By 9:30 p.m., the fire was contained, and Cal Fire crews were clearing the scene.
The cause of the fire has not yet been determined, and the investigation is ongoing.
A CHP spokesperson told NBC 7 the blaze might have been intentionally set. A man in a tank top was seen walking away from a dirt trail near the fire when it started, the officials said. That report has not yet been substantiated.
No injuries were reported; there were also no evacuations ordered during the fire.
No other information was available.