The method
The safety data sheet (SDS), provided by a chemical’s supplier, describes its hazards, physicochemical properties, handling and storage precautions, and emergency measures in case of exposure. Its 16-section structure is internationally harmonised (GHS). Public databases such as PubChem or INRS toxicological data sheets complement or cross-check this information.
To estimate the consequences of a short accidental exposure, several acute toxicity threshold scales exist, and they are not interchangeable. AEGLs (Acute Exposure Guideline Levels, US EPA) define three increasing severity levels (AEGL-1, 2, 3) for several exposure durations. ERPGs (Emergency Response Planning Guidelines, AIHA) follow a similar logic with three levels (ERPG-1, 2, 3), generally for a one-hour exposure. IDLH (Immediately Dangerous to Life or Health, NIOSH) denotes a concentration beyond which a 30-minute exposure irreversibly threatens life or health.
In France, safety reports use regulatory thresholds (irreversible, lethal and significant lethal effects) set by decree, which may rely on AEGLs or on French reference toxicological values depending on the substance.
When to use it
- Before a dispersion calculation, to choose the right threshold concentration to plot.
- Occupational chemical risk assessment (storage, handling, workstation).
- Writing or reading a safety report involving toxic substances.
Watch out for
- AEGL, ERPG and IDLH do not measure the same thing and are not interchangeable: check the exposure duration and severity level targeted before comparing results.
- AEGL, ERPG and DIPPR data are protected; public databases (PubChem, INRS, NIOSH) do not cover every substance or every value.
- An outdated SDS may no longer reflect the current classification: check its date and compliance with the latest CLP regulation.
Steps
- Precisely identify the substance (name, CAS number) and obtain its SDS from the supplier or a public database.
- Note the properties relevant to the intended calculation: boiling point, vapour density, flammability limits, toxicity.
- Choose the threshold scale suited to the use: AEGL for detailed consequence analysis, ERPG for emergency planning, IDLH for responder protection, regulatory thresholds for a safety report in France.
- Check the exposure duration associated with the chosen threshold, consistent with the scenario studied.
- Document the source and version of the value used.
Reference databases and data sheets
List from the Aurorisk catalogue, links checked on 2026-09-26. Confirmed free access is listed first; unknown information is labelled.
| Tool | Source · licence · access | Scope | Description |
|---|---|---|---|
| CAMEO Chemicals (NOAA) ↗ | Public bodyFree | United States | Hazard and reactivity datasheets for thousands of substances. |
| INRS — fiches toxicologiques ↗ | Public bodyFree | France | Summary sheets on substance hazards. |
| NIOSH — Pocket Guide ↗ | Public bodyFree | United States | Pocket guide to chemical hazards (limits, protection). |
| PubChem ↗ | Public bodyFree | United States | Physicochemical and toxicological properties. |
| Seirich (INRS) ↗ | Public bodyFree | France | Free software to assess and prioritise workplace chemical risk (in French). |