Scotsburn Dairy Group’s Truro processing plant was evacuated and shut down early Saturday morning after workers noticed a yellow haze in a part of the facility.

Truro fire officials say nitric acid was leaking from a cleaning line at the plant. The company said the 23 employees on site at the time were taken to hospital for assessment and released. None were injured.

"From what I understand, one of the lines was leaking and it leaked onto a steam line and that created the smoke," Truro Fire Chief Blois Currie says. 

A hazardous materials team from the Truro fire department was called in. It found the source of the leak and confined it to one part of the building, according to the company.

Hazmat team member David Westlake said the concern with nitric acid is it could make it into the lungs.

"It's like any other strong corrosive thing," he said. "Too much of it can cause edema in the lungs and that kind of stuff... if you're not careful and you get overexposed." 

Employees were allowed back inside the plant around 8:30 a.m.

Scotsburn said the plant will remain shut down until Nova Scotia’s Department of Labour completes a final risk assessment.