Firefighters trying to stop the biggest wildfire in Washington State history are being dealt another blow as heavy smoke is forcing the grounding of firefighting aircraft.

“We’re still socked in,” firefighter spokesman Rick Isaacson said. “There’s maybe one mile of visibility.”

The dense smoke continues to cause respiratory problems for firefighters and for residents in the surrounding areas.  In Spokane County, an area of 500,000 residents, has air quality that has been rated “unhealthy.”

“Everybody up here is rubbing their eyes,” fire department spokesman Donnie Davis said. “It’s brutal.”

The fire in Okanogan County is now at 438 square miles and is only 17 percent contained by 1,300 firefighters.

“You can imagine how stretched thin everybody is,” said Dan Dallas, deputy incident commander of the Okanogan fire. “We’re all working without the resources that in a normal year — which I don’t think there is such a thing anymore — that we might have.”

Firefighters are also struggling with swarms of yellow jackets while they fight the fires. It has been reported that a lot of the stings are located on their faces and necks since their equipment leaves very few gaps for the insects to attack.

Crews are being told to stay away from hives until they are removed leaving uncontained fire lines.