(Hillsboro, OR)  --  Nearly two-dozen people are recovering after another possible toxic exposure incident at Intel's Hillsboro Ronler Acres campus.  KATU reports firefighters treated 22 people at the campus yesterday morning for irritation of the respiratory system.  Six people were taken to a hospital.  A hazmat unit responded to the scene, but it's not yet clear what caused the respiratory irritation.  It's the second time in a week that emergency crews had to respond to the facility for employee complaints of respiratory trouble.  Eleven people were hospitalized last Friday with difficulty breathing.  Oregon's Occupational Safety and Health is investigating.