Firefighters, who responded to an early morning fire at an industrial strip center near 44th and Garfield, say they were surprised to learn that it’s a marijuana grow operation. "We try to pull up permits to see what we’re facing," said John Afshar, of the Denver Fire Department. "But in this case it was a surprise to us." The fire started just before 5:30 a.m. in the building on Garfield near 44th, according to officials with the Denver Fire Department. Flames were burning through the roof at one point, fire officials said.