At roughly 7:30 p.m. Tuesday, residents reported seeing a "large white cloud" coming from a private residence on the island, according to Island County Sheriff Mark Brown.
Michael Evers, who lives next to the home near South Bartl Drive and Elger Bay Road, noticed something was wrong right away.
"Immediately, the eyes were watering and coughing and then the back of my throat was killing me," he said.
His wife immediately called Terry Troutvine, who owned the home where the cloud was emanating from.
"He was coughing really bad; he sounded very woozy," Evers said. "(My wife) said 'we're going to hang up right now and you're going to call 911.' "
Medics arrived at the home and found a five-foot-tall steel gas cylinder leaking chlorine, according to Camano Island Fire officials. Troutvine was taken to a local hospital for treatment, and roughly 25 to 30 homes in the area were evacuated or told to shelter in place.
Three other residents of nearby homes also were also taken to the hospital after they began experiencing breathing problems. Four firefighters also were sent to the hospital as a precaution. All were treated and released.
Troutvine, who runs a scrap metal business, said he had found 23 old cylinders at a home in Stanwood and brought them back to his home to be cut up for scrap. The first 20 went fine, but the 21st bottle began leaking chlorine. He said he didn't know what was in the cylinders because they were rusted over and not marked.
A Skagit County HAZMAT team was dispatched to the island to deal with the leak. The canister was safely capped overnight and residents were told they could likely return to their homes Wednesday afternoon.
Meanwhile, Troutvine says he'll never cut open those type of bottles again.