In yesterday’s Advisor, we discussed a hazardous materials (hazmat) transportation requirement that all manually activated on-truck remote shutoff devices for closure of the internal valve on cargo tanks be marked “Emergency Shutoff.” Violations of this requirement have been regularly targeted by Department of Transportation (DOT) roadside inspectors. Sometimes it might feel like the DOT just develops a new rule out of nowhere. Let’s take a look at the real-life situation that precipitated this particular regulation.
In response to a recommendation by the National Transportation Safety Board (NTSB), since October 2005, all manually activated on-truck remote shutoff devices for closure of the internal valve on cargo tanks carrying hazmats are required to be marked “Emergency Shutoff.” Here’s the impetus for this NTSB recommendation.
Note: The NTSB recommendation was made in 1993. The regulation came out in 2003 with a compliance date of October 2005. Just saying.
Started with a Fire
A fire started as gasoline was being transferred from a tank truck to an underground storage tank (UST) adjacent to a maintenance building at a country club in Rockville, Maryland. The tank truck had a cargo tank with a capacity of 4,850 gallons mounted on the truck chassis. The maintenance building, which was used for the storage of paint, fertilizer, pesticides, and grounds-keeping equipment, was destroyed by the fire. Although there were no injuries, officials at the country club estimated the total property damage to be $250,000.
The tank truck and the UST were not required to have or use a vapor recovery system in this operation. Therefore, as liquid gasoline filled the storage tank, gasoline vapors were forced out of the storage tank and into the atmosphere through the fill opening. The ground sloped away from the curbside of the vehicle and the storage tank. As the dense gasoline vapors were displaced from the storage tank, they dispersed along the downhill slope of the ground.
When the fire was noticed, the driver of the truck did not try to stop the truck’s cargo pump or to close internal shutoff valves to stop the flow of gasoline before he fled the scene. He, therefore, could not help the firefighters locate the remote controls for the shutoff valves.
Firefighters Look for Remote Controls
Firefighters decided it would be best to move the truck away from the burning building. One firefighter approached the rear of the tank truck from the driver’s side and closed all the gate valves in a manifold at the rear of the vehicle. Closure of these valves stopped the flow of gasoline from the cargo tank compartments, but gasoline in the discharge line downstream of the manifold could continue to flow through the cargo hose.
The firefighter who initially attempted to move the tank truck was aware that tank trucks are equipped with remote controls to close internal shutoff valves. He would have used the remote control behind the driver’s door to close the valves if he had seen it. A hazmat officer indicated that had the remote control been marked, the marking likely would have prompted him to use the remote control to close the internal shutoff valves before moving the vehicle. Both the firefighter and the hazmat officer stated that marking the remote controls for emergency use would be helpful to emergency response personnel, who may be aware that remote controls are required on cargo tank vehicles that transport hazmats but who are not typically knowledgeable about the configuration of specific vehicles.
NTSB Recommends Marking
The NTSB noted that although the regulations require the driver of a cargo tank vehicle to be knowledgeable about the location and operation of the remote controls, the driver may not be able or available to operate them or to alert emergency responders about their location and operation. Consequently, emergency responders will, in some incidents, be required to locate, identify, and operate the remote controls for the internal shutoff valves to minimize the release of a hazmat.
As a result of this accident, the NTSB recommended that the DOT require that the remote control mechanisms for internal shutoff valves be marked for emergency use on all cargo tanks authorized for the transportation of hazmats.