The Canadian Nuclear Safety Commission says there was a small propane explosion in the acid plant sulphur furnace at Cameco’s Key Lake mill earlier this week.

The CNSC says it happened on Tuesday when workers were initiating the start-up of the plant.

The commission says no one was hurt and there was no measurable impact to the environment, noting the facility safety systems functioned as designed.

The plant produces acid for uranium processing purposes at the mill, but doesn’t process uranium itself.

The commission says Cameco’s Key Lake emergency response team responded appropriately to the event.

The CNSC says it and provincial regulators have been notified.

Meanwhile, the company is investigating the cause of the explosion and possible damage to the internal workings of the sulphur furnace.

The CNSC says Cameco will be providing the commission with a summary of the investigation and corrective actions.