- Operator Exposure Level Test Procedure Sampling, Dispensing, Sieving and Blending Isolator.
- OEL Protocol for IPQC Isolator.
- OEL Protocol for Auto-coater Flexible canopy
- Operator Exposure Level Test Procedure for Compression Machine Isolator
- Operator Exposure Level Sampling Plan
- ISPE Guideline PPT
- Acceptable Operator Exposure Level (AOEL) PPT
- Containment in the pharmaceutical industry
- Total Containment of highly potent or extremely hazardous Substances in the Production ofActive Pharmaceutical Ingredients
Occupational Exposure Level (OEL) is the maximum airborne concentration of a substance (usually an API or potent intermediate) that workers can be exposed to, safely, during their normal working day. In simple terms, OEL tells you “how much is too much” for people handling hazardous or highly potent materials in a pharmaceutical facility.
Why OEL Is Important in Pharma
- Protects operators, maintenance staff, cleaners, and support teams from harmful exposure
- Supports GMP + EHS (Environment, Health & Safety) expectations
- Forms the scientific basis for:
- Selecting PPE (gloves, masks, respirators)
- Designing containment (isolators, RABS, closed systems)
- Planning cleaning, decontamination, and waste handling
- Demonstrates management’s commitment to worker safety and regulatory compliance
How OEL Is Determined
OEL is usually derived by toxicologists based on:
- Toxicity data (NOAEL, LOAEL, animal studies, human data where available)
- Pharmacological potency and therapeutic dose
- Nature of hazard: irritant, sensitizer, carcinogen, reproductive toxin, etc.
- Safety factors to account for variability and uncertainty
The final OEL is typically expressed as a time-weighted average (TWA) over an 8-hour working day (e.g., µg/m³ of air).
OEL and Occupational Exposure Bands (OEBs)
To make OEL easier to apply on the shop floor, many companies convert it into Exposure Bands (OEB 1–5/6). Each band represents a range of OEL values and is linked to:
- Required engineering controls (open handling vs. contained transfer vs. isolator)
- PPE level (basic vs. advanced respiratory protection)
- Special handling and cleaning requirements
Higher OEB = more potent / hazardous = tighter controls.
Applying OEL in Day-to-Day Operations
Once OEL/OEB is defined, it must be translated into practical controls:
- Facility & equipment design: closed charging, split valves, isolators, negative pressure rooms
- Work practices: written SOPs for weighing, charging, sampling, cleaning, maintenance
- PPE selection: gloves, goggles, coveralls, respirators based on OEB
- Environmental & personal monitoring: air sampling, surface wipe tests, operator exposure assessments
- Training & awareness: operators must understand the potency category and required precautions
Documentation & Governance
- OEL values and OEB assignment should be documented, justified, and approved by toxicology/EHS/QA.
- Changes in process, scale, or new toxicology data may require OEL/OEB review.
- OELs should be integrated into risk assessments (e.g., HIRA, FMEA) and change control.
Used correctly, OEL is not just a number—it is a core tool for protecting people while safely manufacturing increasingly potent and complex pharmaceutical products.