LONGVIEW — A large wind-driven fire at a wood products company in Longview has engulfed the site and prompted an air quality advisory for the region that is expected to last into at least Tuesday.

Someone passing by just after 2:30 p.m. Sunday reported a fire at Swanson Bark and Wood Products.

Arriving firefighters encountered a large pile of bark dust burning and spreading to other piles, Longview Police and Fire said. Additional fires in the Longview area, strong winds, visibility issues due to smoke and challenges in accessing the piles created difficulties fighting the blaze.

The fire was out as of about 4 a.m. Monday but dozens of wood piles continue to smolder, authorities said. Swanson Bark and Wood Products has taken over suppression, using loaders and excavators to move the product while extinguishing any fire. Swanson has also contracted with two helicopter services to help with fully putting the fire out. It is expected that the fire could smolder for days, and if winds pick up, could start a larger blaze, Longview authorities said.

Because of the smoke, the Oregon Department of Environmental Quality (DEQ) and Southwest Clean Air Agency issued an air quality advisory for the Portland metro, Lower Columbia River and Southwest Washington area.

The agencies expect the air quality advisory to last into Tuesday and potentially longer, until the fire stops smoldering.

DEQ’s air monitor on Sauvie Island showed unhealthy, or red, air quality Monday morning. Monitors in north Portland and along the Interstate 5 corridor showed moderate, or yellow, air quality.

Smoke can irritate people’s eyes and lungs and worsen some medical conditions. Young children, adults over 65, pregnant women and people with heart disease, asthma or other respiratory conditions are particularly vulnerable.