A process covered under the Risk Management Plan (RMP) rule can be as simple as a single storage vessel (or a group of vessels) in one location, or as complicated as a system of interconnected reactor vessels, distillation columns, receivers, pumps, piping, and storage vessels. The company’s facility is covered under the RMP rule if any of the following processes apply:

• The company stores a regulated substance in a single vessel in quantities above the threshold quantity.
• The company has interconnected vessels that together hold more than a threshold quantity of a regulated substance. These connections need not be permanent, and if two or more vessels are connected occasionally, they are considered a single process for the purposes of determining whether a threshold quantity is present.
• The company has multiple unconnected vessels containing the same substance, if they have determined that they are co-located and thus considered a single process for purposes of the rule.

The following table summarizes processes across schematic representation, description, and interpretation.