11.2 Definitions
- Action Level - Is an airborne concentration of a chemical that when reached or exceeded requires corrective action. The action level for DCM is 1 ppm, which is half the Existing Chemical Exposure Limit (ECEL, 2 ppm).
- As needed monitoring - Exposure measurements taken when there is a change of use.
- De minimis - The threshold concentration for which the regulatory restrictions are not required. For DCM this concentration is 0.01% by weight.
- EPA Short Term Exposure Limit (STEL) - The maximum airborne concentration of a chemical that workers can be exposed to for a short period, typically 15 minutes, without suffering adverse health effects.
- Existing Chemical Exposure Limit (ECEL) - Regulatory occupational exposure limit (OEL) set by the EPA to limit inhalation risks to workers exposed to certain chemicals in a workplace. The ECEL is a maximum average airborne concentration of the chemical that someone can be exposed to in the workplace without experiencing unreasonable risk from inhalation exposure to the chemical.
- Exposure Control Plan (ECP) - This documents actions taken to mitigate occupational exposures and comply with the WCPP at the lab, department, or institutional level. The University of Minnesota’s department of Health, Safety, and Risk Management (HSRM) created a Standard Operating Procedure (SOP) template that may be used as an ECP.
- Hierarchy of Controls - A method of determining which actions should be taken to effectively reduce or remove workplace hazards by identifying the preferred order of exposure controls. These controls, in order of most effective to least effective, are Elimination, Substitution, Engineering Controls, Administrative Controls, and PPE.
- Initial Monitoring - the first round of systematic data collection and observation used to establish a baseline, assess current conditions, or determine the need for further action.
- Owners / operators - Anyone who owns, leases, operates, controls, or supervises a workplace. This includes the University of Minnesota and each PI, instructor, or supervisor who oversees a location where DCM is used or a person who uses DCM.
- Periodic monitoring - Dependent upon the results of the initial and/or repeat monitoring; the frequency for gathering new monitoring data ranges from 3 months to 5 years.
- Potentially exposed person - Any person who may be exposed to a chemical or mixture in a workplace as a result of a condition of use of that chemical substance or mixture. This applies regardless of whether a person is a user of the chemical or an employee. Potentially exposed persons are responsible for complying with the provisions of this Program.
- Prohibited uses - the EPA has established exposure limits for DCM for some conditions of use, including “use as a laboratory chemical” or solvent welding. Nearly all other commercial and industrial uses, such as use as a solvent or paint remover, are prohibited. EPA has a full list of prohibited uses in its Guide to Complying with the 2024 Methylene Chloride Regulation.
- Regulated area - A demarcated area where airborne concentrations exceed, or there is a reasonable possibility they may exceed, the Existing Chemical Exposure Limit (ECEL) of 2 ppm or EPA Short Term Exposure Limit (STEL) of 16 ppm.
- Retailer - An entity that distributes or makes available products to consumers.
- Time-Weighted Average (TWA) - The potentially-exposed person's average airborne exposure in any 8-hour work shift of a 40-hour work week (8-hour TWA), or in any 15-minute reference period covering a specific task where airborne concentrations may instantaneously exceed the full-shift exposure limit (15-minute TWA).
- Workplace Chemical Protection Program (WCPP) - A written program to protect potentially exposed persons in the workplace who are engaged in conditions of use that are not prohibited.