The blaze at the metal recycling plant at 699 Seaport Blvd. started following the sound of a small explosion reported by plant workers about 12:50 a.m., Redwood City Fire Marshal Jim Palisi said.
The smell of smoke and burning plastic was reported as far south as Mountain View, a fire official said. No injuries were reported, he said.
The fire started in a stockpile of “light iron” recyclables, such as discarded appliances, Palisi said.
Embers ignited a second smaller spot fire that was quickly extinguished, he said.
The primary blaze, which sent a large plume of smoke into the air, burned for more than eight hours before being controlled around 9:45 a.m. Tuesday, Palisi said.
Officials advised any residents in the area who smelled smoke to stay indoors with their windows closed, though the advisory was only issued as a precaution, Palisi said.
“The shelter-in-place was issued as an advisory, not a warning,” he said.
Seaport Boulevard reopened about 8 a.m. Tuesday after being closed for more than seven hours, although public access to the recycling facility had remained closed.
On Nov. 10, a fire at the same facility burned in a pile of heavy recyclables and took more than seven hours to control.
Sims Metal Management officials issued a statement in response to the latest fire.
“In coordination with public officials, Sims will thoroughly investigate what could have caused this explosion and fire, including sources of the material in the stockpile. No cause has yet been ruled out,” the statement said.
The company said the timing of the two fires a month apart “raises concerns” and said new policies were implemented after last month’s blaze, including reducing stockpile sizes and separating light iron from auto bodies.