Hazardous Materials Accident Brief - Chemical reaction during cargo transfer

Louisville, Kentucky
November 19, 1998

NTSB Number: HAR-00-02
Accident No: DCA99MZ003
Adopted June 20, 2000
PDF

The Accident

About 7:15 a.m. eastern standard time on November 19, 1998, a truckdriver driving a Matlack, Inc., cargo tank truck arrived at Ford Motor Company's Kentucky Truck 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.

As a result of the incident, about 2,400 people were evacuated from the plant and surrounding businesses, and another 600 local residents were told by authorities to remain inside their homes. Three police officers, three Ford Motor Company employees, and the truckdriver were treated for minor inhalation injuries. Damages exceeded $192,000.

Probable Cause

The National Transportation Safety Board determines that the probable cause of this accident was inadequate training of Ford Motor Company's employees on the company's procedures for unloading bulk hazardous materials. Contributing to the accident was the similar labeling of adjacent pipe connections, which made it possible for the pipefitter to confuse the two connections. Further contributing to the accident was the failure of the U.S. Department of Transportation to establish, and oversee compliance with, adequate safety requirements for unloading hazardous materials from highway cargo tanks.

Recommendations

As a result of its investigation of the November 19, 1998, accident in Louisville, Kentucky, and the June 4, 1999, accident in Whitehall, Michigan,5 the Safety Board issues the following safety recommendations:

To the Research and Special Programs Administration:

Within 1 year of the issuance of this safety recommendation, complete rulemaking on Docket HM-223 "Applicability of the Hazardous Materials Regulations to Loading, Unloading and Storage," to establish, for all modes of transportation, safety requirements for loading and unloading hazardous materials. (I-00-6)

To the Occupational Safety and Health Administration:

Require that facilities where bulk hazardous materials are transferred be equipped with a means of emergency communications. (I-00-7)

To Ford Motor Company:

Distribute written safety-critical procedures for unloading bulk shipments of hazardous materials to all Ford Motor Company employees who are engaged in cargo transfer operations, and conduct initial and recurrent training on the procedures. (I-00-8)

To the American Chemistry Council:

Revise, in cooperation with National Tank Truck Carriers, Inc., the Manual of Operating Recommendations to include specific recommended practices that can be implemented to prevent the unloading of hazardous materials into the wrong storage tank. For example, drivers should personally verify or question all transfer connections before beginning delivery of product. (I-00-9)

Inform your members of the facts and circumstances of the June 4, 1999, accident in Whitehall, Michigan, and the November 19, 1998, accident in Louisville, Kentucky, and emphasize the importance of implementing specific safety-critical hazardous materials cargo transfer procedures and training employees in those procedures. (I-00-10)

To National Tank Truck Carriers, Inc.:

Revise, in cooperation with the American Chemistry Council, the Manual of Operating Recommendations to include specific recommended practices that can be implemented to prevent the unloading of hazardous materials into the wrong storage tank. For example, drivers should personally verify or question all transfer connections before beginning delivery of product. (I-00-11)

Inform your members of the facts and circumstances of the June 4, 1999, accident in Whitehall, Michigan, and the November 19, 1998, accident in Louisville, Kentucky, and emphasize the importance of implementing specific safety-critical hazardous materials cargo transfer procedures and training employees in those procedures. (I-00-12)