BOISE, Idaho (KBOI) — Firefighters are not sure how the fire started at Diamond Street Recycling Center Sunday afternoon and they still aren't sure on how long it will take before it's out for good.

"We have debris piles in excess of 30 feet deep," said Boise Fire Battalion Chief Tom Lovell. "We've got deep seeded fire and it's being very stubborn for us to get to the seed of the fire to be able to get it put out, so it's going to take a lot of man hours."

Michael Toole with the Department of Environmental Quality says the smoke from this fire started moving out Sunday afternoon, but a shift in winds overnight sent it back into the valley. Giving us our dirtiest air quality reading so far this year.

"Early in the morning, I would say between 2 and 3 a.m., we saw levels get up in the red," Toole said. "That's the unhealthy category. We saw that kind of continued through the early morning hours and then later in the morning we were down in the orange."

Fire managers say the smell of smoke was so strong for some residents that they called 911, worried that a fire had started close to their homes.

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