COMMERCE CITY, Colo. — Suncor announced on Facebook it plans to restart a unit that was temporarily shut down after it sent a clay-like catalyst into the air that rained down like ash onto cars and forced two schools to shelter in place.

Suncor said it temporarily shut down a fluidized catalytic cracker unit in its Commerce City refinery after it inadvertently released a non-hazardous clay-like catalyst into the air.

Suncor announced on Facebook it wrapped up its investigation into what happened. The company said it made changes to its start-up procedures to prevent the catalyst from going airborne again.

Suncor said it completed additional checks and final inspections and plans to start up the unit again. During the next few days, Suncor says residents can expect increased flaring and white smoke from the stack.

The company said it’ll take a couple of days to start up the unit and if it doesn’t go as planned, it will stop the process. Suncor said employees will conduct air monitoring in the community while it starts the fluidized catalytic cracker unit.