Details

Parent Category: Safety Info Posts

Category: Hazardous Materials

Published: 01 July 2015

About 7:15 a.m. eastern standard time on November 19, 1998, a cargo tank truck arrived at a Automotobile Plant in Louisville, Kentucky, to deliver a liquid mixture of nickel nitrate and phosphoric acid (a solution designated CHEMFOS 700 by the shipper). A plant employee told the truckdriver to park his vehicle next to the chemical transfer station outside the bulk storage building and wait for a pipefitter to assist him in unloading the chemical. According to testimony, a short time later, the pipefitter arrived at the transfer station and told the driver that he would assist him in unloading the cargo tank. The pipefitter opened an access panel containing six identical pipe connections. Each pipe connection served a different storage tank, and each connection was marked with the plant's designation for the chemical stored in that tank.  The driver told the pipefitter that he was delivering CHEMFOS 700 and then went to the driver's side of the cargo tank and took out a cargo transfer hose. The pipefitter connected one end of the hose to one of the transfer couplers, while the driver connected the other end of the hose to the cargo tank's discharge fitting. Unknown to the pipefitter or the truckdriver, the pipefitter had inadvertently attached the hose to the coupler marked "CHEMFOS LIQ. ADD" instead of to the adjacent coupler marked "CHEMFOS 700." The storage tank served by the coupler marked "CHEMFOS LIQ. ADD" contained sodium nitrite solution.  The driver climbed to the top of the cargo tank, connected a compressed air hose to a fitting, and pressurized the cargo tank. The driver and the pipefitter then reviewed the cargo manifest and bill of lading. The pipefitter signed three different certifications on the cargo manifest, one of which certified that the transfer hose was "connected to the proper receiving line." The pipefitter asked the driver how long it would take to unload the contents of the cargo tank, and the driver told him the transfer would take about 30 to 40 minutes. The pipefitter then left the loading area, leaving the driver to complete the unloading by himself.  About 8:15 a.m., after the air pressure was built up in the cargo tank, the truckdriver started the transfer. When the nickel nitrate and phosphoric acid solution from the truck mixed with the sodium nitrite solution in the storage tank, a chemical reaction occurred that produced toxic gases of nitric oxide and nitrogen dioxide. The driver stated that about 10 minutes after he started the transfer, he saw an orange cloud coming from the bulk storage building. He said he closed the internal valve of the cargo tank to stop the transfer of cargo and waited for someone to come out of the building. After several minutes, the pipefitter ran out of the building and gestured for the driver to stop the unloading process.  Here is the full NTSB investigation:

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