This is Rehab 3 and is operated by the Zone 3 Explorers in South King County (Washington State). The vehicle was formerly used by the Kent Fire Department as Haz-Mat 76. It is currently kept at Fire Station 14 in Renton and will respond to larger incidents in South King County.
Here's a unique rig, at least to me. Orange County, FL's Rehab 1, or Crapper 1, as it's affectionately called is this 2007 Int'l 7600/E-One, Job #132005, and 2006 Wells Cargo toilet trailer.