The Tacoma Fire Department says lithium-ion batteries is the likely cause of Monday's early morning scrap yard fire.
The fire at Simon Metals scrap yard produced smoke for hours, weakening the air quality around downtown. For nearly three hours the Port of Tacoma shut down until the conditions began to improve around 1 p.m.
The fire began around 2 a.m. and by 10 a.m. air quality around downtown Tacoma fluctuated between moderate and unhealthy for sensitive groups.
The Tacoma Fire Department advised people to stay indoors and limit physical activity outdoors.
"For those bothered by the smoke, we recommend staying indoors and limiting physical activity for those that remain outside. TFD has been coordinating with state and local agencies to address potential environmental concerns," the department tweeted.
The fire broke out around 2 a.m. in the 2200 block of E River Street.
The fire was under control by 10 a.m.
