Wednesday, March 16, 2011

New PHMSA Bulk Transfer Rule - Risk Assessment

As I mentioned last Friday, PHMSA has finally (this was first addressed in January 2008 – 73 FR 916) published the NPRM for their bulk hazardous material loading and unloading regulations for cargo tank motor vehicles. One of the basic requirements for this new rule is that a risk assessment must be completed for all hazmat tank truck loading and unloading operations.

Who is Responsible

A new section, §177.831, is added to the Hazardous Materials Regulations (HMR) laying new requirements on each “person who loads, unloads, or provides transfer equipment to load or unload a hazardous material to or from a cargo tank motor vehicle”. This statement is clear, but its application in the real world might be a tad more difficult. HAZMAT loading operations are normally conducted by facility employees but the person who actually unloads a tank truck at the receiving location may be a facility employee, an employee of the supplier providing the material, or a truck driver working for a third party.

Generally speaking the hazmat employer responsible for the loading or unloading operations is responsible for conducting the risk assessment. There are confounding factors that may spread some of that responsibility around. Where the hazmat employee conducting the transfer operations is not a facility employee and the facility requires “unique operational procedures” there is a dual responsibility for the assessment. If a facility provides transfer equipment, a hose for example, for a transfer operation conducted by a separate hazmat employer, there is again a dual responsibility for the conduct of the risk assessment.

In fact, even where facility personnel are responsible for transfer operations, “the motor carrier must conduct a risk assessment and develop operating procedures that are specific to the cargo tank involved in the transfer operation” (76 FR 13319).

It seems that the only case where there is not some sort of dual responsibility for conducting the risk assessment is “where the motor carrier is primarily responsible for the safety of the transfer operation, such as at a business or residence”. The preamble explains that this is typically found at gasoline delivery to commercial gas stations or propane deliveries to homes.

Risk Assessment

Section 177.831(a) describes the newly required risk assessment as a “a systematic analysis to identify and evaluate the hazards associated with the specific loading or unloading operation”. It subsequently explains that the “analysis must be appropriate to the complexity of the process and the materials involved in the operation” {§177.831(a)(2)} and then lists three specific areas that should be addressed:

“(i) The characteristics and hazards of the material to be loaded or unloaded;

“(ii) Measures necessary to ensure safe handling of the material, such as temperature or pressure controls; and

“(iii) Conditions that could affect the safety of the loading or unloading operation, including access control, lighting, ignition sources, and physical obstructions.”
For those unloading operations that are entirely the responsibility of the carrier, PHMSA does not intend for this rule to require a location specific risk assessment to be required where large numbers of such locations would make that requirement impractical. They specifically state in the preamble to the NPRM that such carriers would not need to “conduct a separate risk assessment of each residence or retail outlet (i.e., gas station) to which it delivers propane or gasoline, but may instead assess the overall risk of such operations and develop operating procedures that apply generally to such operations” (76 FR 13320).

Equipment to be Assessed

The wording of the description of the equipment that is intended to be included in the safety assessment is very important. The new regulatory language states “including [emphasis added] any device in the loading and unloading system that is designed specifically to transfer product between the internal valve on the cargo tank and the first permanent valve on the supply or receiving equipment (e.g., pumps, piping, hoses, connections, etc.)” {§177.831(a). [NOTE: there is a missing closing parenthesis at the end of this description in the NPRM.]

It is important to remember that the word ‘including’ in this context means that the description that follows is not the only definition of the term; just a common example being used for illustrative purposes. This is an important distinction. Other equipment could also be part required assessment. For example, vent lines allowing for pressure equalization between the cargo tank and the storage tank, gas lines used to pressurize the cargo tank during unloading operations, and loading scales used to gauge the amount of material added to the cargo tank.

Even so, I think the example provided in the current language is overly restrictive. At one facility where I worked we had permanent unloading lines for all of the raw materials that we received into bulk storage tanks. One end of the stainless steel flex lines were attached to facility piping by a flanged connection. At the other end of the flex line was a manual valve. A strict interpretation of the exemplar provided in the would thus limit the area of concern for the assessment to the short section of on-truck piping between the internal valve and the manual valve on the end of the flex line.

Characteristics and Hazards

The term “characteristics and hazards of the material” is going to be very important to the implementation of this regulation. If PHMSA narrowly interprets this terminology to mean those ‘characteristics and hazards’ that are addressed in the HMR then the hazard assessment will be narrowly focused. The resulting assessments will be limited to looking at things like flammability, corrosivity and toxicity; all important characteristics and hazards to be sure.

PHMSA needs to expand the definition of this term to include reactivity and expand it beyond the narrow ‘no water’ definition of reactivity found in the HMR. Numerous unloading incidents occur every year when the wrong material is off-loaded into a storage tank. These reactions can range from the violently exothermic reactions of a strong acid and base; the reactions that explosively release gasses like bleach and aqua ammonia; to the slower but just as catastrophic polymerization reactions that produce enough heat over time to produce uncontrollable decomposition reactions.

These types of reactions are not covered in the HMR because they are a miniscule risk in transit. When these reactions happen in loading operations they are limited in scope because the incompatible material being loaded on-top-of is typically very small in volume relative to the material being loaded. If the catastrophic reaction does take place it seldom moves outside the front gate.

At fixed facilities where material is being added to a storage tank the possibility of sufficient quantity of the ‘other chemical’ being present is greatly increased. The problem is frequently compounded by the fact that the level in the ‘wrong tank’ has not been properly checked and the tank is overfilled. With hazardous chemicals where the storage tank is vented back to the tank wagon to avoid toxic releases that overfilling can force the reacting products back into the tank wagon, expanding the hazard area significantly.

Use of Assessment

The importance of this hazard assessment cannot be over stated. The results of this assessment will become the basis for the development of the operating procedures that will be used to ensure that these transfer operations are conducted in a safe manner. I’ll look at the requirements for those procedures in a future blog post.

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