Residents of an apartment complex in midtown were evacuated due to a potential HAZMAT incident Thursday morning, officials say.

According to Capt. Tom Carpenter of Tucson Fire Department, there was an odor coming from a unit in the building at 3003 N. Alvernon Way, south of East Fort Lowell Road.

Firefighters arrived at 11:13 a.m., minutes after a passerby reported the odor, a department press release said.

Tucson bomb squad officers were called to use a robot equipped with air monitoring equipment to investigate the apartment.

No hazardous substances were found but investigators believe the apartment was vandalized.

Three residents were treated for difficulty breathing and cleared by medical personnel at the scene.

No other injuries were reported.

Contact reporter Gloria Knott at gknott@tucson.com or 573-4235. On Twitter: @gloriaeknott

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