Employee was painting the interior space on a 6000-gallon water tank. He was wearing a fresh air respirator; the compressor was outside with a line that ran into the confined space through an access point on top. The tank attendant didn't get a response so 911 was called and entry was restricted until the air was confirmed clear. By the time the all clear was issued, firefighters arrived and performed rescue operations. The employee was taken to Kootenai Medical Center. He had a pulse and was breathing on his own, but was still unresponsive. His PPE included a Survivair Respirator with compressor, full enviro air suit, Tychem SL chemical suit, another paint suit underneath, and a Bullard hose system.