April 7 (UPI) — Fire ripped through a Kimberly-Clark paper goods warehouse early Tuesday in Ontario, Calif., spewing smoke and ash into the sky in a tremendous black plume.

The blaze was first reported about 1:45 a.m., and responders from the Ontario Fire Department found heavy smoke and fire when arriving. More than 100 emergency personnel from that and at least four other departments worked to contain the fire into the day.

Officials said about 20 people were at the 1.2 million-square-foot warehouse when the fire broke out; there were no initial reports of injuries.

The fire department warned area residents, especially seniors and children, of poor air quality connected with heavy smoke and ash from the blaze and advised people to remain inside.

Ontario Deputy Fire Chief Mike Wedell told KNBC-TV in Los Angeles that the fire department identified the blaze as “suspicious in nature.” Police were questioning a warehouse employee in connection with the fire.

A Kimberly-Clark representative told KCBS-TV in Los Angeles that a third-party partner operated the warehouse and that the company was working with that partner and local authorities. Kimberly-Clark, based in Irving, Texas, manufactures mostly paper products, including brands such as Cottonelle, Scott, Huggies and Kleenex.