TORRANCE (CBSLA) — Activists and concerned residents gathered Saturday to mark the fifth anniversary of the Exxon Mobil refinery explosion in Torrance.

FILE — Refinery explosion at the ExxonMobil Refinery in Torrance, Calif., on Feb. 18, 2015. The blast occurred in a gasoline-processing unit, sending ash and smoke in to the air. (Ted Soqui/Corbis via Getty Images)

READ MORE: Water Main Break Forces Road Closure In Marina Del Rey

They’re calling for safety improvements at the facility following the Feb. 18, 2015 blast that threatened to release thousands of pounds of acid into nearby neighborhoods.

READ MORE: Multiple Victims Wounded In Whittier Shootings During Vigil

The Torrance Refinery Action Alliance wants hydrofluoric acid, which is used to produce high octane fuel additives, to be banned.

The 2015 explosion caused serious property damage and led to a hike in gas prices that experts say cost California and drivers $2 billion.

MORE NEWS: Two Dead In Lancaster Crash

Four people were injured in the blast.