EMA guideline on health-based exposure limits
Guidance for setting health-based exposure limits for risk identification when different medicinal products are manufactured in shared facilities.
HBEL / PDE
Health-based exposure limits
The EMA guideline is a key reference for deriving substance-specific health-based exposure limits (HBELs/PDEs) for risk identification in shared facilities. ICH Q3C and Q3D also contain PDEs, but for defined impurity groups: residual solvents and elemental impurities.
ICH guidelines
PDE and impurity-risk references
ICH Q3C and Q3D provide PDE values for specific impurity groups. Q3A and Q3B address impurity and degradation-product assessment and control. ICH M7 addresses DNA-reactive mutagenic impurities and related acceptable-intake approaches. Scientific reviews discuss how these principles may be relevant to PDE work for genotoxicants and how OEB information may inform interim PDE approaches in selected circumstances. These applications are case-specific; the guidelines and exposure values are not interchangeable.
ICH Q3C(R9) — Residual solvents
Guidance on residual solvents, including PDE values for listed solvents.
ICH Q3D(R2) — Elemental impurities
Risk assessment and control of elemental impurities, including PDE values for listed elements.
ICH Q3A(R2) — Impurities in new drug substances
Guidance on reporting, control and qualification of impurities in new drug substances.
ICH Q3B(R2) — Impurities in new drug products
Guidance on reporting, control and qualification of degradation products in new drug products.
ICH M7(R2) — Mutagenic impurities
Guidance on assessment and control of DNA-reactive mutagenic impurities, including acceptable-intake approaches to limit potential carcinogenic risk.
Occupational exposure
OSHA databases and exposure-limit references
OSHA Occupational Chemical Database
Search chemical information, including exposure limits and related occupational safety resources.
OSHA Annotated PEL Tables
Review OSHA permissible exposure limits alongside selected alternative occupational exposure limits.
OSHA: 29 CFR 1910.1000 — Air contaminants
Official US general-industry standard covering listed airborne contaminants and related exposure limits.
OSHA Chemical Exposure Health Data
Search published workplace sampling records. These records are exposure-sampling data, not a list of PEL values.
HBEL/PDE and OEL assessments may use overlapping toxicological evidence, but the values are not interchangeable: a PDE is expressed as a daily dose, while an OEL is a workplace-air concentration over a defined period. OSHA PELs are US regulatory limits where applicable. A database entry or the absence of a listed limit is not a substitute for a substance-specific assessment.
Further reading
Scientific reviews on PDE and OEL derivation
These peer-reviewed review articles provide scientific background on setting pharmaceutical PDEs and OELs. They are review articles, not regulatory guidelines.
Approaches for setting occupational exposure limits in the pharmaceutical industry
Varun Ahuja and Mohan Krishnappa. Journal of Applied Toxicology. 2022;42:154–167.
Challenges in setting permitted daily exposure limits for pharmaceuticals: A review
Varun Ahuja and Mohan Krishnappa. International Journal of Risk & Safety in Medicine. 2022;33(1):49–64.
PDE, OEL, OEB and impurity-specific acceptable-intake approaches share some toxicological principles but have different scopes and units. They should be applied case by case; no direct conversion should be assumed without scientific justification.
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