One person died after an ammonia leak Thursday at an ice-making plant in an industrial area of ​​Kamloops, B.C.

The leak began inside the Arctic Glacier Ice building at 790 Sarcee St. East in the Mount Paul Industrial Park around 10:30 a.m. PT. Paramedics responded and took three people to hospital – one in critical condition and two stable.

The Interior Health Authority says four people have arrived at the Royal Inland Hospital in relation to the incident; the number varies slightly from what paramedics initially said, as some may not have gone by ambulance.

All four were treated as needed and released, according to Interior Health.

The person who was taken to hospital by ambulance in critical condition has since died, police said.

RCMP constable. Crystal Evelyn said the RCMP will investigate the cause of the leak.

About six other patients in stable condition were assessed at the scene, British Columbia Emergency Health Services said.

A hazmat team from Kamloops Fire Rescue responded to the leak, as did WorkSafeBC. The industrial park is located north of downtown Kamloops, across the South Thompson River.

Deputy Fire Chief Ryan Cail said crews didn’t realize they were dealing with ammonia until they arrived to find a strong odor in the air.

“Teams learned once on site that it was actually a cloud of ammonia that had escaped from a cylinder in the facility inside the building,” Cail told CBC. News.

Chris Leader, who works about 200 yards from the site of the leak, was having lunch in his truck when he says he heard a “pop” and saw a “big big” plume of smoke coming out of the Arctic Glacier Ice building. He said the smoke rose about 30 meters and blew east.

“[It was] kinda scary,” he said. “It was ammonia, and you know what it can do.”

He said he and his colleagues were ordered to evacuate as quickly as possible, but were not told how long they should stay away.

Ammonia is a colorless but pungent gas used in refrigeration systems, power generation and manufacturing.

Inhaling low levels of ammonia can irritate the eyes and respiratory tract, but large amounts can be fatal. Three people were killed by a leak while trying to repair ice-making equipment at a hockey rink in Fernie, British Columbia, in 2017.

An RCMP officer on scene confirmed Thursday’s leak originated from the Arctic Glacier Ice facility. WorkSafeB.C. and the BC Coroner’s Service are investigating the incident.

Evelyn said most roads around the scene have reopened except for the immediate Sarcee Street area.

In a tweet, the City of Kamloops said the scene was considered stable and evacuees could “go about their business in the area.”