United States (Arizona) - Fire officials are trying to figure out what started a warehouse fire in the eastern Phoenix suburb of Gilbert that generated thick black smoke that could be seen for miles. Mesa fire Capt. Mark Justus says the blaze ignited Monday afternoon and involved mostly materials in a backyard storage area behind Farnsworth Wholesale, a plumbing wholesale company.

The Arizona Republic reports that dozens of fire trucks from Gilbert, Tempe, Chandler and Mesa were at the scene and an aerial tanker sprayed water for about an hour.

State environmental officials allowed nearby residents to return by 7 p.m. Monday but told them to minimize exposure outdoors because of smoke fumes.

A spokesman for Farnsworth says the facility will likely be closed for several months.

Written and photos by Associated Press