This is one of the most common misunderstood RMP/PSM compliance issues for facilities that use rail cars as storage tanks and or use "tube trailers" as storage tanks. EPA has been clear since 1998 on how these rail cars that are hooked up to the process and those that are "stored on spurs" are to be managed in regards to RMP threshold determination and "defintion of a process".
Taken from EPA's RMP Q&A's (PLEASE click on the link to visit the database to ENSURE you are getting UP-TO-DATE information)
Click Here to read article on RMP/PSM coverage for unloading tranportation containers.
Q1. The definition of stationary source does not apply to transportation, including storage incident to transportation (40 CFR Section 68.3). Are chemicals in a tank car (e.g., tanker truck or rail car) therefore exempt from threshold determination?
A1. The chemicals in the tank car are exempt only if the tank car is in transportation. EPA considers a container to be in transportation as long as it is attached to the motive power (e.g., truck or locomotive) that delivered it to the site (63 FR 643, January 6, 1998). If the tank car is detached from the motive power, and therefore no longer in transportation, the contents of the tank car must be considered in the threshold determination.
Q2. (NOTE - this Q&A is no longer present on the Federal EPA Q&As) I have a covered toxic chemical that is shipped to my facility by railcar. Only one railcar at a time is connected to the process for the purpose of unloading. However, up to ten additional full railcars may be located on a nearby rail spur that is owned by the facility. The ten railcars are delivered by locomotive, unhitched, and left on the company's spur. Using a trackmobile, facility personnel routinely re-position the empty railcars and they move the full railcars into unloading position. The ten railcars of toxic material are separated from the process area. Additionally, the PHA team did not discover a credible scenario in which a railcar located on the holding spur could be involved in a release event (i.e. no initiated event was uncovered that could cause one or more of the railcars located on the holding spur to be included in a specific hazard scenario).
My question is do I have to include the 10 rail cars located on the holding spur with my RMP?
The concern is that if we list all ten railcars, the railcar being unloaded, and the amount of toxic material laid-up in the process it may lead to an exaggerated concern that large amounts of toxic material are actually being "processed". While in actuality only a relatively small amount of the toxic material is being used in the process area (i.e. subjected to increased pressure and temperature).
A2. EPA considers tank cars carrying regulated substances not connected to a locomotive to be stationary sources. Assuming that the ten cars you mentioned are connected to one another and are not connected to a locomotive, they would be considered a separate process under your RMP. The lone rail car and the chemical process it's connected to would be considered another covered process if they are located far enough away from the ten cars that a fire or explosion of one would not affect the other. Therefore, you should have one RMP with two covered processes and list the quantities in each process. To address your concerns about an accurate perception from the public, you should understand the differences between a chemical process and a covered process as it refers to 40 CFR, Part 68. A covered process can be any process that has a regulated substance present in more than a threshold quantity as determined under §68.115. Process means any activity involving a regulated substance including any use, storage, manufacturing, handling, or onsite movement of such substances, or combination of these activities. For the purposes of this definition, any group of vessels that are interconnected, or separate vessels that are located such that a regulated substance could be involved in a potential release, shall be considered a single process. Therefore you must report the 10 cars on the spur in your RMP. In order to explain that they are not involved in the "chemical process" area where temperature and pressure are being altered, you can explain this in your executive summary.
Q3: (NOTE - this Q&A is no longer present on the Federal EPA Q&As) I have a company that has an off-loading and on-loading dock. Railroad cars enter the property and are filled with a commercial propane or butane mixture. During the filling of the tank cars, the locomotive engine is disconnected until all the cars are full and ready for transport. Will I have to consider these railroad tank cars under the risk management program rule?
A3: The risk management program rule does not apply to mobile sources or sources being actively transported. Because the railroad cars are not in active transport and have been disconnected from the locomotive or truck cab, the tank cars fall under the definition of process (in this case, storage). The railcars will have to be evaluated for applicability (meeting the threshold quantity of > 10,000 pounds of the regulated flammable substance). If it is determined that the railcars meet the applicability requirement, then a risk management plan should be submitted to EPA by June 21, 1999.
Q4: (NOTE - this Q&A is no longer present on the Federal EPA Q&As) My business loads a commercial grade butane mixture onto railcars for transport to another facility. Since the rail cars being loaded will hold more than 10,000 pounds of mixture and are disconnected from the locomotive engine, I know that they are considered as storage and fall under the risk management program rule. How do I determine the threshold quantity since it is a mixture? Secondly, how do I report this in the data elements of the risk management plan submittal form (RMP*SUBMIT)?
A4: For flammable mixtures, the risk management plan rule (40 CFR 68.115 Threshold Determination) stipulates that " if the concentration of the flammable regulated substance contained in the mixture comprises 1% or greater by weight, then for the purposes of determining whether more than a threshold quantity is present at the stationary source, the entire weight of the mixture shall be treated as the regulated substance unless the owner or operator can demonstrate that the mixture itself does not meet the criteria for flammability of flash point below 73 degrees F and boiling point below 100 degrees F. The owner or operator shall document these flash point and boiling point measurements or estimates." When preparing the risk management plan, the data element ( 1.17.c.1 Name of Chemical) allows you to list it as a "flammable mixture" if you have a NFPA-4 flammable mixture containing regulated flammables. List all of the regulated substances contained in the mixture; however, only report the quantity of the entire mixture, not the individual substances.
Tank Truck and Tube Trailers
Q1. Tube trailers carry bulk liquids that are stacked in a rack type arrangement on the back of a truck trailer. This arrangement often is used to carry highly hazardous materials such as anhydrous hydrogen chloride. The tubes are manifolded together, but usually only one tube at a time is connected to a process for loading and unloading. Are "tube" trailers considered a single process?
A1. If the "tube" trailers remain in transportation, the contents of the trailers are exempt from threshold determination. If the tubes no longer are in transportation, the entire grouping of tubes must generally be considered a single process, since they are co-located such that they could be involved in the same accident.
Q2. My stationary source has a process that contains a maximum of 4,000 lbs. of a regulated substance that has a 5,000 lb. threshold quantity. When the level of the regulated substance in the process reaches 1,000 lbs., a delivery truck comes on site and connects to the process to replenish the supply. The tank on the truck holds 10,000 lbs. of the regulated substance. Must I consider the amount of the regulated substance in the truck's tank to be a part of my process while the transfer hoses are connected, and therefore complete an RMP for this process?
A2. No, the regulated substance in the truck's tank would not be considered part of your process. A regulated substance in a truck's tank is considered "in transportation," and thus not part of a source's process, as long as the tank is attached to the truck's motive power (i.e., its cab or engine). Since in your case the motive power remains attached to the tank, only the amount of regulated substance your source accepts must be counted towards the threshold quantity. Since your source will have no more than 4,000 lbs. of a regulated substance even after taking delivery, it will not exceed the threshold quantity for the substance.