Glossary

Action Level (AL) is a concentration established by a company or regulatory program that triggers additional evaluation, monitoring, investigation, or preventive controls before an exposure limit is exceeded.

An Action Level is not necessarily a regulatory exposure limit and does not by itself determine compliance status.

Note: For EPA TSCA Workplace Chemical Protection Programs, compliance is based on the applicable ECEL and EPA STEL. Organizations may establish internal Action Levels as a proactive exposure management tool.

Administrative Controls are work practices, procedures, policies, or scheduling methods used to reduce employee exposure to workplace hazards.

Administrative controls are typically implemented when engineering controls alone cannot adequately control exposures.

Examples:

• Limiting exposure duration
• Rotating job assignments
• Written work procedures
• Restricted access to exposure areas
• Employee training programs

Air-Purifying Respirator (APR) is a type of respirator that removes contaminants from ambient air through cartridges, canisters, or filters before the air is inhaled by the wearer.

APRs are appropriate only when adequate oxygen is present and airborne concentrations are within the approved operating limits of the respirator and filter media.

Chemical Abstracts Service Number (CAS Number) is a unique numerical identifier assigned to a specific chemical substance by the Chemical Abstracts Service (CAS).

CAS Numbers are widely used by regulatory agencies, manufacturers, laboratories, and safety professionals to accurately identify chemicals regardless of differences in trade names or common names.

Example:

• Methylene Chloride CAS Number: 75-09-2

Compliance Determination is the documented conclusion that employee exposure monitoring results are either:

• At or below the applicable EPA ECEL and EPA STEL, resulting in a determination of Compliant.
• Above the applicable EPA ECEL or EPA STEL, resulting in a determination of Non-Compliant and requiring investigation and corrective action.

Note: Company-defined warning levels, action levels, or exposure trends may be used as internal management tools; however, EPA TSCA compliance is based upon whether employee exposures exceed the applicable ECEL or EPA STEL established for the regulated chemical.

Corrective Action is a planned activity implemented to eliminate the cause of a nonconformance, compliance issue, or exposure exceedance and prevent recurrence.

Corrective actions may include engineering modifications, procedural changes, additional training, equipment repairs, or implementation of additional exposure controls.

De Minimis means a quantity or concentration that is considered too small or insignificant to warrant regulatory concern under a specific regulatory program or requirement.

The definition and applicability of a de minimis threshold may vary depending on the particular EPA regulation, reporting obligation, or risk management requirement.

Example:

• A chemical present below an established de minimis concentration may qualify for reduced reporting or notification obligations, depending on the applicable regulation.

Dermal refers to the skin or exposure occurring through contact with the skin.

Dermal exposure may occur when chemicals come into direct contact with the skin and are absorbed into the body or cause localized irritation, burns, sensitization, or other adverse health effects.

Example:

• An employee handling liquid solvents without chemical-resistant gloves may experience dermal exposure.

Engineering Controls are physical modifications to equipment, processes, or facilities designed to reduce or eliminate employee exposure to workplace hazards at the source.

Engineering controls are generally considered the preferred method of controlling chemical exposures because they do not rely on worker behavior or personal protective equipment.

Examples:

• Local exhaust ventilation
• Closed transfer systems
• Isolation enclosures
• Process automation

EPA Short-Term Exposure Limit (EPA STEL) means a short-duration occupational exposure limit established by EPA under TSCA for certain regulated chemicals.

The EPA STEL is typically expressed as a 15-minute Time-Weighted Average (TWA) and is intended to protect workers from adverse health effects associated with brief periods of elevated exposure. Where an EPA STEL has been established, employers must ensure that worker exposures do not exceed the applicable short-term limit.

Example:

• Chemical: Methylene Chloride
• EPA STEL: 16 ppm (15-minute TWA)
• If a 15-minute exposure sample exceeds 16 ppm, the exposure exceeds the EPA STEL and corrective actions are required, even if the employee's 8-hour TWA exposure is below the ECEL.

Existing Chemical Exposure Limit (ECEL) means an occupational exposure limit established by the U.S. Environmental Protection Agency (EPA) under the Toxic Substances Control Act (TSCA) for specific existing chemicals that have been determined to present an unreasonable risk to workers from inhalation exposure.

An ECEL represents the maximum allowable airborne concentration of a regulated chemical to which a worker may be exposed, typically expressed as an 8-hour Time-Weighted Average (TWA). Facilities subject to EPA's Workplace Chemical Protection Program (WCPP) must ensure that potentially exposed persons are not exposed above the applicable ECEL.

Example:

• Chemical: Methylene Chloride
• ECEL: 2 ppm (8-hour TWA)
• If employee exposure monitoring indicates an 8-hour TWA exposure greater than 2 ppm, the exposure exceeds the ECEL and corrective actions are required.

Exposure Assessment is the process of evaluating the nature, magnitude, frequency, duration, and route of employee exposure to chemical, physical, or biological hazards.

Exposure assessments may involve air sampling, observational studies, review of work practices, and evaluation of existing controls to determine worker risk and regulatory compliance.

Exposure Control Plan (ECP) is a written program that documents the measures used to prevent or reduce employee exposure to hazardous chemicals.

An ECP typically describes exposure sources, engineering controls, administrative controls, personal protective equipment (PPE), training requirements, monitoring activities, corrective actions, and procedures for maintaining compliance with applicable occupational exposure limits.

Frank R. Lautenberg Chemical Safety for the 21st Century Act (Lautenberg Act) is the 2016 amendment to TSCA that significantly expanded EPA's authority to prioritize, evaluate, and regulate existing chemicals based on risk.

The Lautenberg Act requires EPA to evaluate unreasonable risks to workers, consumers, and the environment and authorizes the development of risk management rules to address identified risks.

Hierarchy of Controls is a systematic approach for reducing workplace hazards that prioritizes exposure control methods based on effectiveness.

The hierarchy generally ranks controls as: elimination, substitution, engineering controls, administrative controls, and personal protective equipment (PPE).

The most effective controls eliminate the hazard, while PPE is typically considered the last line of defense.

Immediately Dangerous to Life or Health (IDLH) refers to an airborne concentration of a substance that poses an immediate threat to life, would cause irreversible or delayed adverse health effects, or would interfere with an individual's ability to escape from a hazardous environment.

IDLH values are commonly used when selecting respiratory protection and emergency response procedures.

Industrial Hygiene (IH) is the science and practice of anticipating, recognizing, evaluating, and controlling workplace environmental factors that may cause injury, illness, impairment, or discomfort among workers.

Industrial hygiene activities may include exposure assessments, air monitoring, hazard evaluations, control recommendations, and verification of control effectiveness.

Inhalation Exposure is exposure that occurs when an individual breathes airborne contaminants such as gases, vapors, mists, fumes, dusts, or fibers into the respiratory system.

Inhalation is often the primary exposure route evaluated under EPA TSCA Existing Chemical Exposure Limits (ECELs) and EPA STELs.

Example:

• Workers transferring volatile solvents may experience inhalation exposure if vapors are released into the work area.

Management of Change (MOC) is a formal process used to evaluate, review, approve, communicate, and document changes that could affect worker health and safety, chemical exposure risks, environmental compliance, or regulatory obligations.

Changes subject to the MOC process may include modifications to chemicals, processes, equipment, operating conditions, engineering controls, work practices, personal protective equipment (PPE), exposure control measures, facilities, or organizational responsibilities.

The MOC process helps ensure that potential hazards and compliance impacts are identified and addressed before implementing the change.

Example:

• A facility replaces a regulated solvent with a different chemical.
• The change is evaluated through the MOC process.
• Exposure monitoring requirements, PPE needs, employee training, and TSCA compliance obligations are reviewed before implementation.

Negative Exposure Determination (NED) is a documented conclusion that employee exposure monitoring results demonstrate worker exposures are consistently below the applicable occupational exposure limit under normal operating conditions.

A NED may support reduced monitoring frequency when permitted by the applicable regulatory requirement and adequately documented.

Occupational Exposure Limit (OEL) is a health-based airborne concentration limit established to protect workers from adverse health effects associated with chemical exposure.

OELs may be established by regulatory agencies or professional organizations and may include Time-Weighted Averages (TWAs), Short-Term Exposure Limits (STELs), or Ceiling Limits.

EPA ECELs are examples of OELs established under TSCA.

Occupational Safety and Health Administration (OSHA) is the federal agency within the U.S. Department of Labor responsible for establishing and enforcing workplace safety and health standards.

OSHA regulations may apply concurrently with EPA TSCA requirements. Employers must comply with all applicable OSHA standards in addition to any TSCA risk management requirements.

Parts Per Million (ppm) is a unit of concentration commonly used to express airborne concentrations of gases and vapors.

One ppm represents one part of a substance per one million parts of air.

EPA ECELs, EPA STELs, and occupational exposure limits are frequently expressed in ppm.

Example:

• An airborne concentration of 2 ppm means that two parts of the chemical are present in one million parts of air.

Personal Breathing Zone (PBZ) is the hemisphere surrounding a worker's nose and mouth, generally within a radius of approximately 6 to 9 inches, from which breathing air is drawn.

Personal exposure monitoring samples are typically collected within the PBZ to estimate an employee's inhalation exposure.

Personal Protective Equipment (PPE) consists of specialized clothing or equipment worn to reduce exposure to workplace hazards that may cause injury or illness.

PPE may include respirators, gloves, protective clothing, eye protection, face shields, hearing protection, and protective footwear.

PPE should be used in conjunction with engineering and administrative controls and not as the sole means of exposure protection whenever feasible.

Polyvinyl Alcohol (PVA) is a synthetic polymer commonly used in the manufacture of chemical-resistant gloves and other protective materials.

PVA gloves provide excellent protection against certain organic solvents but are not suitable for use in wet environments because water can degrade the material and reduce its protective effectiveness.

Example:

• PVA gloves may be selected when handling specific solvents that readily penetrate nitrile or latex gloves.

Potentially Exposed Person (PEP) is an individual who may reasonably be expected to be exposed to a regulated chemical during the performance of work activities or while present in areas where chemical exposure may occur.

Under EPA TSCA risk management rules, PEPs may include employees, contractors, and other workers with potential exposure to regulated substances.

Regulated Area is a designated workplace location where employee exposure to a regulated chemical may exceed an applicable exposure limit or where specific protective measures are required.

Access to regulated areas may be restricted to authorized personnel and may require the use of prescribed controls or personal protective equipment.

Representative Exposure Monitoring is the collection of exposure data from employees, operations, or work conditions that are expected to reflect the highest reasonably foreseeable exposures within a group of similarly exposed workers.

Representative monitoring may be used to characterize exposures across an operation when supported by appropriate documentation and technical justification.

Similar Exposure Group (SEG) is a group of employees who have similar job tasks, work practices, materials, processes, and exposure potential such that their exposure profiles are expected to be comparable.

SEGs are commonly used to organize exposure monitoring programs and evaluate worker exposure risks.

Time-Weighted Average (TWA) is the average airborne concentration of a chemical to which a worker is exposed during a specified time period. For most EPA ECELs, compliance is evaluated using an 8-hour TWA exposure assessment, which accounts for variations in exposure throughout the work shift.

Toxic Substances Control Act (TSCA) is the federal law administered by the U.S. Environmental Protection Agency (EPA) that provides authority to regulate the manufacture, processing, distribution, use, and disposal of chemical substances in the United States.

TSCA authorizes EPA to evaluate chemical risks and establish risk management requirements to protect human health and the environment, including worker protections and exposure limits for certain existing chemicals.

United States Environmental Protection Agency (EPA) is the federal agency responsible for protecting human health and the environment through the administration and enforcement of environmental laws and regulations.

Under TSCA, EPA evaluates chemical risks and may establish requirements such as Workplace Chemical Protection Programs (WCPPs), Existing Chemical Exposure Limits (ECELs), and EPA Short-Term Exposure Limits (EPA STELs).

Workplace Chemical Protection Program (WCPP) is a TSCA-required program established by EPA risk management rules for certain chemicals.

The WCPP requires facilities to implement measures to protect workers from unreasonable chemical exposure risks, which may include exposure monitoring, engineering controls, administrative controls, personal protective equipment (PPE), training, recordkeeping, and compliance with applicable ECELs and EPA STELs.