Hundreds of apartments and homes in central Gilroy experienced a tense four hours on March 23, as hazardous materials crews contained a potentially deadly chlorine gas incident.
City firefighters said that a maintenance worker at the Bellagio Villas Apartments, 1129 Montebello Drive, miraculously escaped injury when the apartment complex pool house filled with chlorine gas.
The National Institute for Occupational Safety and Health describes the gas as a “chemical warfare choking agent.” It was used in the trench warfare of World War I.
Gilroy Division Fire Chief Jim Wyatt, the incident commander, said that about 10:30am the maintenance worker was pouring 14 gallons of chlorine into a filtering system dispenser inside a pool house next to the outdoor pool in the center of several apartment structures.
The man said he thought he was pouring water into the dispenser from a old plastic juice jug to dilute the pool chemical. Instead, the jug contained concentrated muriatic acid, which is used as a cleaner.
There was an instant chemical reaction, and a noxious greenish-yellow gas bubbled up from the dispenser, and began to fill the pool house. The man poured water into dispenser, then left quickly, calling 911 as he shut the doors behind him—saving his life, and containing the growing danger inside the structure.
The gas is heavier than air, and can cause irreversible lung damage, and fatalities, if individuals are exposed to a high enough concentration.
Once the arrived at the scene in a few minutes, firefighters quickly notified all apartment residents and went door to door in the neighborhood, advising people to stay inside and keep their windows closed, because of a possible chemical leak.
“We checked the outside with our gas meters, and there was no leakage, except a little by the door,” said Wyatt.
Wyatt established a perimeter at the both ends of Montebello Drive, and called the nearest county Hazardous Materials Response Team, which arrived from Los Gatos before about 1pm, and began donning their brightly colored, inflated full-body protective gear.
The City of San Jose’s Hazardous Incident Team also arrived, to provide backup and support for the county crew. The San Jose unit had full, silver-colored foil suits with headgear and gas masks.
Wyatt said he also alerted El Roble Elementary School, about two blocks away. He asked them to keep any children from the affected neighborhood at the school, so they would not have to walk home into the danger zone. School officials alerted parents about the potential danger, and cars began to stack up at Wren and Montebello outside of the cordoned-off area.
As long as the gas was contained in the pool house, Wyatt said there was no danger. He said if it escaped they would have to work to dissipate it in the air, reducing its potential effects.
Streets were closed at Santa Barbara Drive and 3rd Street and Montebello Drive and Wren Avenue for more than three hours.
Wyatt and the hazardous teams came up with a solution to ease the neighborhood’s crisis. They stretched fire hoses from the street to the pool house, and the firefighters in protective gear began spraying thousands of gallons of water into the pool house, diluting the gas to safe levels by 2:30pm
“They’re going to hose it down, let it settle, then check their meters,” said Wyatt during the tense procedure.
“If it’s not off-gassing, then we have done our job,” he said.
At that time a report came over the radio from hazardous materials team: “We are at point-four, and no reaction.” “Affirmative.” “Fourteen, twenty-five hours.”
“They just checked the parts-per-million, and they see no reaction,” said Wyatt. Below 0.5 parts per million is the safe level for chlorine gas.
“That means the chemical reaction in the room is no longer off-gassing,” he said.
“Now they are going to spray down the room.” “All clear. We are on our way out. Tell the decon team to get ready. ”
The maintenance worker, standing by Wyatt’s side, said he was going to leave, to go pick up his daughter at El Robles, as the fire crews stepped out of their protective gear.