SAN FRANCISCO (KRON) -- The San Francisco Fire Department said crews were on the scene of an active hazardous materials (HazMat) incident Friday at the Presidio Golf and Concordia Club, located at 8 Presidio Terrace. One person was transported to the hospital, according to SFFD. Nearby residents an d businesses were asked to avoid the area. SFFD crews were dispatched to the scene at 12:48 p.m. SFFD told KRON4 that hazardous materials were discovered inside the club, and crews have since determined the material was muriatic acid that someone mixed with chlorine. In a social media post just after 3:30 p.m., "Our HazMat units and fire companies are working to assess the situation, identify any potential hazards, and ensure the safety of the public and our first responders." BCN reported that a pool cleaner was injured at the Presidio golf course by a chemical release while mixing chlorine with muriatic acid, SFFD said. The man was working on the jacuzzi hot tub in the clubhouse of the Presidio Golf Concordia Club at 8 Presidio Terrace when he inhaled fumes about 12:48 p.m., Capt. Mariano Elias said. The combination of chlorine and muriatic acid produces deadly chlorine gas. The man took himself to a local hospital and was in stable condition, Elias said. The chemicals, including a 55-gallon drum, were outdoors when the incident occurred, he said. "We contained the material and once that was done, the Department of Public Health took it over and they're going to dispose of it properly," Elias said. Bay City News contributed to this report. ...read more read less