Accident Report Detail

​On April 2, 1971, at Berwick, Maine, a hose used for transferring a bulk liquid chemical cargo from a motor carrier's tank semitrailer to a tannery storage tank was incorrectly attached to a fill fine leading to an indoor open-top tank. When the transfer began, the cargo mixed with the incompatible chemical stored in the indoor tank, resulting in a chemical reaction which generated toxic hydrogen sulfide gas. Six tannery workers died from inhalation of this toxic gas.

​The National Transportation Safety Board determines that the cause of this accident was the- failure of the carrier's drivers and the tannery foreman to establish an error-free exchange of information required to accomplish the safe transfer of the cargo from the vehicle into a plant storage tank. The likelihood of this failure was increased by the absence of instructions or training in information validation procedures to be followed during such exchanges, and by the absence of markings, devices, or other measures on the vehicle or tannery property which would have permitted such validation to be made unilaterally by either party.