Bozeman, Mont. ? Firefighters battling a wildfire that has blackened nearly 290 square miles and burned 26 homes faced a new challenge, authorities said Wednesday: bees.

The blaze near Bozeman, which started with lightning on Aug. 22, has forced hundreds to evacuate. After being grounded by smoke for a day, firefighting helicopters returned to work Wednesday, pouring water on the fire that was 45 percent contained.

Bee stings among firefighters have surged to as many as 50 a day, information officer Joan Dickerson said. Some of those stung required medical attention.

“We’ve had a couple of our leaders taken to the hospital,” she said, but added that she had no explanation for the surge in stings.