Language selection

News release

Associated links (M20P0230)

Poor battery maintenance contributed to the explosion on the tug Risco Warrior in Bute Inlet, British Columbia

Richmond, British Columbia, 2 March 2022 — Today, the Transportation Safety Board of Canada (TSB) released its investigation report (M20P0230) into an explosion on board a vessel at Mellersh Point in Bute Inlet, British Columbia (BC), drawing attention to the importance of having detailed instructions for battery maintenance.

On 07 August 2020 at approximately 1230 Pacific Daylight Time, an explosion occurred in the tug Risco Warrior’s battery compartment, while the tug was holding the barge Western Carrier against the dock at Mellersh Point in Bute Inlet, BC. The vessel sustained structural damage, and two crew members on board sustained minor injuries.

The investigation found that the continuous unregulated charging of the battery caused the water in the electrolyte to break down into hydrogen and oxygen and evaporate, which, combined with the lack of maintenance, caused overheating and internal damage to the battery plates. It was also determined that there was no ventilation in the battery compartment and therefore, flammable hydrogen gas accumulated, causing a hazardous condition. A spark from an unknown source then ignited the accumulated hydrogen gas, causing the explosion.

Throughout the investigation, it was identified that the Risco Warrior did not have a formal Safety Management System (SMS) nor was it required to under the SMS regulations. Additionally, no procedures were in place for the safe operation of the vessel, or for dealing with emergencies, as required by the Canada Shipping Act, 2001. Safety management and regulatory surveillance are safety issues on the TSB Watchlist 2020. As demonstrated in this occurrence, if a vessel operator does not provide formal safety management processes, then there is an increased likelihood that hazards will not be identified and their associated risks will not be mitigated. Also, in the absence of comprehensive regulatory surveillance and enforcement, there is a risk that instances of unsafe equipment and operating practices on tugs of less than 15 GT, such as in this occurrence, will continue.

Following the occurrence, the operator took several safety actions. Forced air ventilation systems have been introduced into the battery compartment. New batteries, including battery boxes, accessories, charging systems and new alternator have been installed. Written policies and procedures for conducting safe operations and dealing with emergency situations have been developed.

See the investigation page for more information.


The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

For more information, contact:
Transportation Safety Board of Canada
Media Relations
Telephone: 819-994-8053
Email: media@tsb.gc.ca