A Highland man pleaded not guilty Monday to charges accusing him of setting a massive fire at an Ontario warehouse last week, authorities said.

Chamel Abdul Karim, 29, appeared in court in Rancho Cucamonga and is facing state and federal arson charges in connection with the fire at a Kimberly-Clark paper products warehouse.

Investigators allege Karim intentionally set the blaze Tuesday while about 20 employees were inside the building. All were able to evacuate safely, authorities said.

The fire caused an estimated $500 million in damage and forced the warehouse to close as cleanup continued.

Officials said investigators were also reviewing social media videos that allegedly show someone setting fires inside the warehouse while complaining about pay.

Karim worked for NFI Industries, a third-party logistics company affiliated with Kimberly-Clark.

If convicted, he could face life in prison. He is scheduled to return to court May 6.