The National Transportation Safety Board has issued a Marine Accident Report detailing its investigation of the November 4, 2019, explosion of barge IB1940, owned by J O Equipment LLC, in the Illinois Marine Towing (IMT) Heritage Slip on the Chicago Ship and Sanitary Canal, near Lemont, Ill.
The explosion occurred when the barge was being prepared for cleaning after its cargo of acetone had been unloaded. No injuries or pollution were reported in connection with the explosion. The barge was declared a total constructive loss, valued at $1.75 million.
IMT had been contracted to remove any residual acetone from the IB1940’s cargo tanks, ventilate the tanks, and wipe down any wet spots inside the tanks in preparation for the next load of cargo, which was scheduled to be crude ethanol. This procedure was referred to as a “strip-and-blow cleaning,” says the NTSB report.
The stripping process was to be performed using a vacuum truck connected to stripping lines (pipes) aboard the barge to extract residual liquids from the barge’s cargo tanks. The blowing process was to be performed using venturi-type air movers, powered by compressed air, to force fresh air into the cargo tanks and expel any residual vapors. These air movers had no moving parts and were typically used for ventilating hazardous areas. At the IMT facility, filtered and dried compressed air was provided to a manifold that ran down the length of the dock, with valve connections for flexible compressed air hoses at various locations on the dock.
In the report, the NTSB says the probable cause of the explosion was incomplete procedures that did not incorporate the safety instructions included in the Illinois Marine Towing Facility Operations Manual for electrical bonding of air movers to barges.
The NTSB’s investigation revealed that while Illinois Marine Towing had written guidance to workers for tasks related to barge cleaning operations before the explosion, the documents did not include all procedures identified in the Facility Operations Manual, specifically guidance for bonding air movers to the barge.
Following the accident, says the NTSB, Illinois Marine Towing updated its standard operating procedure for liquid barge strip-and-blow cleanings to a 13-page document that includes instructions for stripping tanks, verifying that all residual product has been removed from tanks, inspecting air movers before leaving the shop, and ensuring the bonding strap (which grounds the air mover) is attached and tested for electrical continuity between the air mover horn and the bonding clamp.
Download the full NTSB report HERE.