Four Tips for Loading and Unloading Cargo Tanks

A driver miscommunicates critical information to facility personnel during delivery of corrosive material that was then unloaded into the wrong storage tank containing incompatible materials. Adding to the confusion, it’s the driver’s first delivery to this location. The comingling of incompatible materials emits a vapor affecting the breathing of the driver and facility employee resulting in both being transported to a hospital for treatment. Also, approximately 100 gallons of the mixture are released at the time of unloading.

This is the stuff of nightmares for EHS professionals. But, it’s one of many horror stories related by the Pipeline and Hazardous Materials Safety Administration (PHMSA) concerning the loading and unloading of cargo tank motor vehicles. Today we offer four tips for safely loading and unloading cargo tank trucks.

According to PHMSA, human error is a major contributing factor for incidents occurring during loading and unloading operations including, but not limited to:

• Failing to attend/monitor loading/unloading operations;
• Leaving a valve in the wrong position either before, during, or after loading/unloading operations;
• Improperly connecting transfer equipment;
• Overfilling cargo tanks or receiving tanks; and
• Using defective/deteriorated devices and equipment.

Four tips for safely loading and unloading cargo tank motor vehicles

Tip 1. Ensure proper connection between the vehicle, transfer equipment, and facility vessel(s).

• Have the right transfer equipment for the intended use;
• Make sure the components of the transfer equipment connection are compatible with each other, the vehicle, and the facility vessel;
• Make certain that any replacement parts are similarly compatible; and
• Use a procedural checklist to ensure proper transfer equipment connections.

Tip 2. Ensure compatibility of the hazardous material to be transferred with the contents (if any) of the containment vessel (e.g., storage tank, cargo tank) and the containment vessel itself.

• Select the correct facility vessel for the transfer of hazmat;
• Make sure the receiving vessel (i.e., the cargo tank vehicle or the facility container) is free of incompatible contents or residue and make sure they have been certified as such;
• Find out if the cargo tank vehicle is in dedicated service for compatible hazmat;
• Make sure there is proof that the cargo tank vehicle was properly cleaned before loading; and
• Make sure visual aids (e.g., chemical name, Globally Harmonized System (GHS) label) are on receiving containers to indicate the appropriate receiving vessel.

Tip 3. Take steps to prevent overfills or unintended releases.

• Make sure there is enough space in the receiving vessel for the hazmat;
• Confirm the quantity to be transferred;
• Ensure that valves are in the correct position consistent with operating instructions;
• Make sure level gauges, alarms, and safety interlocks are functioning properly and that they have been maintained and inspected; and
• Have the appropriate personal protective equipment (PPE) available in the event of a spill or release.

Tip 4.  Ensure that proper procedures are followed at all facilities.

• Make sure all personnel are trained on the facilities’ procedures;
• Make procedural instructions available and accessible and confirm that they include instructions on emergency response;
• Make a procedural checklist available and accessible; and
• Make sure that the transfer connections and discharging/receiving vessels are clearly indicated.

Tomorrow we will review training recommendations for employees who are charged with loading and unloading cargo tank vehicles.