SDS Section 3: Concentration Ranges, Trade Secrets, and Information Limits

Section 3 is useful only if the reader preserves the difference between a disclosed fact, a permitted range, and missing information. A range is not an invitation to choose a convenient exact concentration. An ingredient that does not appear on the sheet is not necessarily absent from the product.

For an employer, the practical question is whether the available composition information supports the decision at hand: identifying an exposure, selecting protective equipment, reviewing a substitution, or completing a program-specific reporting calculation. Sometimes it supports a bounded screening result. Sometimes the correct disposition is to obtain more information.

Download the composition review, uncertainty record, and supplier request template (Word).

Define the question before using the percentages

Start with the exact product identifier, supplier, grade, component, and SDS revision. Record the unit and concentration basis used by the sheet. A weight percentage, a volume percentage, a concentration in solution, and a worker's airborne concentration describe different things.

Identify what the calculation or review is supposed to establish. A CAS number may help identify a sampling method; it does not establish how much reaches the worker. A formulation range may support a conservative screening calculation; it does not necessarily supply the exact component quantity needed for a particular determination. Write the question down before selecting a number.

The Section 3 glossary explains the disclosure framework. The method below addresses the harder step: deciding what can responsibly be concluded from an incomplete composition record.

What gets disclosed, and why the list can be incomplete

1910.1200 Appendix D distinguishes substances from mixtures. For substances, the information includes chemical identity and identifiers, with classified impurities or stabilizing additives that contribute to classification. For mixtures, the disclosure provisions address ingredients classified as health hazards that are present above the relevant cutoff or concentration limit, or that present a health risk below it.

That doesn't mean publishing the complete commercial recipe. A nonhazardous carrier may not appear as a separately disclosed ingredient. Conversely, a health-risk ingredient below an ordinary cutoff can still call for disclosure. There is no single percentage below which every ingredient can always be ignored.

Record the chemical name and CAS number or other unique identifier as provided. If a CAS number is unavailable or claimed as a trade secret, Appendix D to 1910.1200 calls for the source of the unique identifier to be indicated. Do not substitute a guessed CAS number from a similar trade name. A family of petroleum substances or a variable-composition material may need further technical information before the employer can select a suitable exposure-assessment approach.

An ingredient's classification is also not automatically the mixture's classification. Appendix A to 1910.1200 contains health-hazard classification criteria and mixture procedures. An employer reviewing a supplier's product should not recreate the classification by adding percentages and disregarding the applicable criteria, test data, or other evidence.

Distinguish the reasons for a range

Appendix D to 1910.1200 ordinarily calls for the exact concentration, with permitted exceptions for a supported trade-secret claim, batch-to-batch variability, and groups of substantially similar mixtures. The reason matters. A trade-secret statement and a variable-batch range do not mean exactly the same thing, even when the printed percentages look similar.

Under current 1910.1200(i)(1), a supported trade-secret claim can protect the specific chemical identity and/or concentration information. Under the same paragraph, the SDS still discloses the chemical's properties and effects and identifies the withheld information as a trade secret. When the concentration or concentration range is withheld, the prescribed range provisions apply.

The prescribed ranges are:

1910.1200(i)(1)(v) calls for the narrowest possible prescribed range and permits a limited combination of consecutive ranges within the specified 0.1–30% provisions when its conditions are met. 1910.1200(i)(1)(vi) permits a narrower range. Those provisions don't permit choosing any broad range or combining any two entries in the table.

These are supplier disclosure provisions. A downstream employer should identify an apparent inconsistency and ask for clarification rather than silently repairing the SDS or declaring a trade-secret claim invalid without examining the facts.

Read a real mixture without reverse-engineering it

The U.S., California CARB-compliant WD-40 Multi-Use Product Aerosol SDS, prepared November 13, 2024, provides an instructive composition example. Section 3 reports an LVP aliphatic hydrocarbon at 45–50%, an additional aliphatic hydrocarbon entry at 10–<25%, petroleum base oil at <35%, and carbon dioxide at 2–3%. The two hydrocarbon entries use CAS 64742-47-8; carbon dioxide uses CAS 124-38-9. The sheet includes a trade-secret statement.

Those are reported ranges for this identified sheet, not a complete formula or independently measured composition. Preserve the two hydrocarbon entries separately in the review. Ask the supplier how they should be treated if their shared identifier affects an aggregation or exposure decision; do not casually collapse them into one exact concentration.

Two of the disclosed ranges demonstrate the mathematics without inventing a facility inventory. Let M be a separately verified product mass, in pounds, on the same weight basis as the SDS. The first reported hydrocarbon range corresponds to 0.45M–0.50M; the carbon dioxide range corresponds to 0.02M–0.03M. Neither expression establishes the exact mass in a particular container or batch.

The midpoints, 47.5% and 2.5%, are calculated conveniences, not concentrations disclosed by the manufacturer. Selecting them as if they were exact replaces a known interval with an unsupported point estimate.

What range calculations can and cannot establish

For a bounded screening calculation, retain the lower and upper bounds and the actual inequality. “Less than 25%” does not mean exactly 25%, even if a particular conservative screening method uses that endpoint as a bound. Record that choice and explain whether it is permitted for the decision being made.

Independent ingredient ranges are not a set of exact concentrations meant to add to 100%. Adding every upper bound may describe no physically possible formulation. Subtracting the listed ingredients from 100% does not reveal the identity or exact amount of the undisclosed remainder. Do not rename that remainder “water” or “nonhazardous ingredients” without supporting information.

A decision is sensitive to uncertainty when different values within the supported range could change its outcome. In that situation, obtain better information or use a technically justified, program-appropriate conservative method. Do not select the value that produces the preferred answer.

Keep occupational exposure calculations separate

Product composition does not directly predict airborne exposure. Volatility, temperature, application, aerosol generation, work rate, enclosure, ventilation, and exposure duration can all affect what reaches the worker. A minor formulation ingredient can contribute materially to airborne exposure; a large product fraction may behave differently.

Use composition to identify hazards and the assessment questions, then obtain a suitable exposure basis. 1910.134(d)(1)(iii) requires identification and evaluation of respiratory hazards, including a reasonable estimate of exposure and identification of the contaminant's chemical state and physical form. It does not authorize replacing that assessment with the ingredient's product percentage.

Section 8 and the applicable standards supply exposure-limit and control information. Sections 2 and 11 help explain mixture hazards and health effects. If a confidential ingredient affects glove selection, analytical-method selection, or respiratory protection, formulate the question specifically enough that the supplier or qualified reviewer can address the decision.

Environmental reporting needs its own analysis

An ingredient appearing in Section 3 does not automatically trigger Tier II (40 CFR 370) or TRI (40 CFR 372) reporting. Each program has its own applicability, chemical definitions, exemptions, thresholds, aggregation, and reporting rules.

For example, 40 CFR 370.14 distinguishes EHS components from non-EHS hazardous chemicals and addresses mixture-versus-component reporting. An SDS composition interval is one input to that analysis. It does not establish facility-wide quantities, the applicable reporting option, or eligibility for an exemption.

Document which program and method the reviewer used, how quantity and concentration evidence were obtained, and how uncertainty was handled. A reporting conclusion should not rest on a spreadsheet that silently treats every SDS midpoint as exact.

Ask the supplier for information that resolves the decision

A useful request identifies the product and SDS revision, the proposed task or reporting question, the specific ambiguity, and the information needed. Ask whether a range reflects batch variability, substantially similar formulations, or withheld concentration information; whether differently described rows represent separate fractions; and whether the supplier can provide an appropriately supported range, batch information, or technical assessment.

Do not request the entire proprietary formula merely because additional information would be convenient. Explain the occupational-health need if disclosure of protected identity or concentration is essential. Nonemergency requests under 1910.1200(i)(3) have specific requirements concerning the written request, need, why substitute information is insufficient, confidentiality procedures, and confidentiality agreement.

Where a treating physician or other licensed health care professional determines that a medical emergency exists and the information is necessary for emergency or first-aid treatment, 1910.1200(i)(2) provides for immediate disclosure to that professional. Prior execution of a written statement of need or confidentiality agreement is not a prerequisite to that emergency disclosure; the rule permits follow-up documentation as circumstances allow.

The companion includes an ordinary supplier clarification request and a separate reminder to use the applicable trade-secret process when necessary. A routine purchasing email is not automatically a complete 1910.1200(i)(3) request.

Record uncertainty as an unresolved technical issue

Keep a short decision record with five elements: the question, verified information, unresolved uncertainty, why it matters, and disposition. Assign an owner for the clarification and identify what can and cannot proceed while it is unresolved.

For the real-mixture example, a supported record could accept the listed intervals as the review inputs while holding a calculation that needs an exact concentration. A separate exposure assessment might proceed with a suitable method that doesn't need disclosure of the full formula. Those are different decisions; one unresolved question does not justify inventing an answer to either.

Record the supplier's response with the reviewed revision and reassess any affected conclusions. Preserve confidential information appropriately. A worksheet that contains protected ingredient information or medical details should not be circulated as a general training handout.

Apply the HCS transition to the product being reviewed

The current 1910.1200(j) dates are:

1910.1200(j)(4) permits compliance with the specified earlier version, the revised version, or both during the applicable transition. Identify the product type and governing version before judging a range disclosure. The existence of a transition does not make a guessed concentration defensible.