An unusual industrial accident has brought work to a halt at a water treatment plant in the Town of the Blue Mountains. According to a statement put out by the town, it happened on Wednesday while contracted employees were working an overnight shift at the Thornbury Wastewater Treatment Plant, located at Grey Street North and Bay Street East. Just before 10 p.m., the town says, the employees were repositioning equipment on a temporary in-water clear stone berm. A berm is a large ridge, usually made of either a large mound or a large rock and temporarily placed in the water. The town says during this work, the berm became unstable, causing an excavator to go on the water. Crews then got to work trying to take the first excavator out of the water. The town says during recovery efforts, the berm became unstable again, causing a second excavator to fall into the water. Clearway Construction, the town’s primary contractor on the outfall pipe assembly and installation happening at Thornbury Wastewater Treatment Plant, has contacted its senior management and its health and safety department, the town says. According to the town, due to the instability of the berm, the site must be assessed before further recovery efforts continue. Precautionary spill treatment measures were deployed around both excavators, the town says. So far, no release of fuel, oil or other fluids has been observed or reported, according to the town. In the meantime, the incident has been reported to the Canadian Coast Guard, Fisheries and Oceans Canada, Ministry of the Environment, Conservation and Parks, Ministry of Natural Resources and the Grey Sauble Conservation Authority. The town adds it is working with contractors to ensure recovery work is completed safely and with appropriate environmental safeguards.