HELENA -- Gov. Brian Schweitzer traveled to the command post for Montana's colossal Derby Mountain wildfire Wednesday as the blaze entered its third week and firefighters toiling in hot, dry conditions faced still another challenge: bees.

The trip to the Derby Mountain camp in south-central Montana was the second for Schweitzer, who was to be briefed by fire managers, then take an aerial tour if the sky was clear enough. The fire that started with lightning Aug. 22 has spread across 185,000 acres, or 289 square miles. It has burned 26 homes.

Other states with major fires Wednesday included Washington and Nevada.

Officials said 45 percent of the Derby Mountain blaze was contained. Containment consists of natural or constructed barriers, such as bulldozer lines, that may restrict a fire's spread.

Information officer Joan Dickerson said the west side of the fire was particularly active Wednesday, when temperatures were in the mid 80s, humidity remained low and wind blew from the east.

Bee stings among firefighters have been occurring at the rate of 40 to 50 a day, said Dickerson, adding some of those stung required medical attention for sensitivities.

''We've had a couple of our leaders taken to the hospital,'' she said.

Dickerson said she had no explanation for the surge in bee stings.

An evacuation order that applied to 265 homes remained in effect, three days after it was issued. An alert for evacuation readiness covered another 20 homes.

Smoke from the Derby Mountain fire and others triggered air-quality warnings in southwestern Montana. The Department of Environmental Quality said the air in Bozeman and in the area of the fires was ''very unhealthy'' while Butte's air quality was ''unhealthy.'' Air was not healthful for sensitive groups of people in Livingston, Helena, Missoula, Whitefish, Kalispell and Libby, the DEQ said.