A worker at the Ministry of Natural Resources and Forestry fish hatchery in Dorion has refused to work in a specific area because of high radon levels.

Radon is a naturally occurring gas that can cause lung cancer.

Levels at the hatchery have been monitored for decades. The ministry says ventilation improvements were made over the years, but radon levels are currently above Health Canada's guidelines.

The work refusal has triggered an inspection by the Ministry of Labour.

It has not issued any orders yet, but a spokesperson for the MNRF said the current monitoring program will be updated.

MNRF communications officer Joshua Henry told CBC News in an email that “the situation is being managed by adjusting fish culture practices in the area of concern in order to reduce the amount of time that other staff spend in that area. This is consistent with Health Canada's guidelines.”

Five people normally work at the hatchery.

The Ministry of Labour was told about the work refusal Nov. 21.

"We were notified about a work refusal related to radon levels,” William Lin told CBC News.

“We have dispatched an inspector and an investigation is ongoing.”