Methodology

SDS HQ generates Safety Data Sheets compliant with the U.S. OSHA Hazard Communication Standard (29 CFR 1910.1200), updated by the May 2024 final rule that aligns the U.S. workplace standard with the seventh revised edition of GHS (with select Rev 8 provisions).

We do not currently produce SDSs valid in:

• European Union (CLP / REACH)
• United Kingdom (UK CLP)
• Canada (WHMIS 2015)
• Other GHS-implementing jurisdictions (Mexico, Japan, China, Korea, Australia, etc.)

A document generated here may be acceptable in non-U.S. workplaces that recognize HCS 2024 as substantially equivalent, but verifying that is the user's responsibility, not ours.

The engine applies the GHS Rev 9 Annex I rule set as adopted by HCS 2024, computing all 14 GHS hazard classes — ten health, three physical (flammable liquids, oxidizing liquids, corrosive to metals), and the aquatic environmental class — first-principles from composition, not by template-matching against a library of finished SDS. Specifically:

• Acute toxicity (oral, dermal, inhalation): ATE additivity per §3.1.3.6, using published ingredient ATE values where available and the GHS Rev 9 Table 3.1.2 converted point estimates otherwise. The §3.1.3.6.2.3 "corrected formula" is applied automatically when more than 10% of the mixture has unknown acute toxicity for the route.
• Skin / eye / respiratory irritation and corrosion: additivity with the standard GHS cutoffs (1% Skin Corr. 1; 10% Eye Irrit. 2; etc.). ECHA Annex VI specific concentration limits (SCLs) override the generic cutoffs where published.
• Sensitization: 0.1% trigger for Cat 1A sensitizers without a published SCL (per §3.4.2.2.4 / §3.4.4.2.4), 1.0% for Cat 1B and unspecified-subcategory.
• STOT-SE / STOT-RE / CMR: ECHA harmonized category assignments with substance-specific SCLs where published.
• Aquatic toxicity: additivity with M-factors per §4.1.3.5, summing acute and chronic separately.
• Physical hazards: driven by user-supplied physical properties (flash point, boiling point, etc.) plus ingredient heuristics. Not a substitute for a calibrated test result on the finished mixture.

Every classification result includes an audit-trail calculation string showing which substance contributed what, what cutoff or formula applied, and which Purple Book section governed the decision.

The six GHS bridging principles (§1.3.4) — dilution, batching, concentration, interpolation, substantially similar mixtures, and aerosols — are implemented in the engine for inheriting a previously-classified mixture's result. They are being wired into a saved-mixtures workflow and are not yet applied automatically during authoring.

The hazard library is layered, in this precedence order:

1. Curated manual overrides — hand-verified entries for substances commonly found in biotech / IVD reagent formulations (TRIS, methanol, polysorbates, isothiazolinones, etc.). Each entry cites its source SDS and verification date.
2. ECHA Annex VI harmonized classification — Annex VI of CLP Regulation (EC) 1272/2008 contains the EU's legally harmonized classifications; our current build embeds 4,186 substance entries (ATP20–ATP22). We use this as substance-level hazard data because the underlying chemistry (acute toxicity, CMR endpoints, aquatic toxicity, etc.) does not change at a national border, even though SDS legal validity does.
3. PubChem — fallback lookup for substances absent from the curated library and Annex VI. Used for naming, CAS resolution, and last-resort hazard data.

These feed Section 15 of generated SDSs: the EPA TSCA inventory flag, SARA §313 and CERCLA reportable quantities, and the California Prop 65 list (cancer / reproductive listings with their listing dates), plus a library-wide watchlist covering ECHA SVHC and TSCA §6 restricted substances.

• Section 14 (Transport): the engine performs US DOT (49 CFR §172.101 / §173.150) classification of the mixture — UN number, proper shipping name, hazard class, and packing group, with most-stringent-PG escalation and a marine-pollutant determination. Because IMDG (sea) and IATA (air) share the UN Model Regulations basis, that classification carries across modes; but mode-specific operational details — IMDG EmS / segregation groups and IATA packing instructions and quantity limits — are not modeled. Confirm those with your carrier for regulated shipments.
• State right-to-know lists: in addition to California Prop 65, SDS HQ cross-references every ingredient against the full published New Jersey, Pennsylvania, Massachusetts, Rhode Island, and Minnesota Right-to-Know lists — 3,295 substances transcribed from each state's authoritative source of record — surfacing matches in Section 15 and the regulatory watchlist. Each list is a dated edition that may lag the current statute, and the Minnesota and Rhode Island lists are non-exclusive: a missing flag is not proof a substance is unlisted, so verify against the live list for compliance-critical shipments into those states.
• Physical properties: measured properties of the finished mixture (flash point, kinematic viscosity, density, etc.) are user-supplied. The engine cannot infer them from ingredients with the same confidence it brings to chemistry endpoints. Provide measured values where regulation requires them.
• Section 11 (Toxicology): per-ingredient toxicology is drawn from ECHA harmonized (Annex VI) classifications and a curated override set, with IARC / NTP carcinogen cross-references for common industrial and laboratory carcinogens. Where no data exists for an endpoint we render "No data available" rather than inventing a value, and carcinogens outside the curated cross-reference set are flagged as such rather than left blank.
• Pictograms and labels: generated SDSs carry the hazard pictograms required by HCS 2024, and SDS HQ generates print-ready GHS container labels (drum, bottle, and vial sizes) with the signal word, pictograms, hazard and precautionary statements, supplier identification, and a scan-to-SDS QR code. Workplace secondary-container labeling alternatives and non-US label formats (e.g. EU CLP) are not yet generated.
• Engine version drift: every classification is stamped with the engine version that produced it. A published sheet renders from the snapshot frozen at publish time, so SDS HQ re-checks it against the current engine and flags it in the library if the classification would now differ — one click reopens it to refresh and re-publish. (Drafts always re-classify live when opened.)

We absorb regulatory updates on a monthly cycle. Each cycle reviews OSHA Federal Register notices, OSHA Letters of Interpretation, EPA TSCA inventory updates, and California OEHHA Prop 65 list changes. Material changes are summarized in the change log with the engine version they shipped in.

SDS HQ provides a software tool for authoring Safety Data Sheets. The user (and their employer) is responsible for verifying the accuracy and completeness of any SDS produced for their specific use case, jurisdiction, and distribution scope. The tool is not a substitute for licensed regulatory expertise where the chemistry, end-use, or jurisdictional posture is materially complex. Use at your own risk.