A Safety Data Sheet (SDS) must follow a standardized 16-section format established by the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). In the United States, OSHA’s Hazard Communication Standard enforces this format, and a final rule published in May 2024 updated the standard to align with the seventh revision of the GHS. The sections must appear in a specific order, and each one has defined data requirements that manufacturers, importers, and distributors are expected to meet.
The 16 Required Sections
Every SDS must present information in the same sequence. This isn’t optional. The standardized order ensures that emergency responders, workers, and safety professionals can find critical information quickly, regardless of the product or manufacturer. Here are all 16 sections in order:
- Section 1: Identification of the substance/mixture and company
- Section 2: Hazard identification
- Section 3: Composition/information on ingredients
- Section 4: First-aid measures
- Section 5: Firefighting measures
- Section 6: Accidental release measures
- Section 7: Handling and storage
- Section 8: Exposure controls/personal protection
- Section 9: Physical and chemical properties
- Section 10: Stability and reactivity
- Section 11: Toxicological information
- Section 12: Ecological information
- Section 13: Disposal considerations
- Section 14: Transport information
- Section 15: Regulatory information
- Section 16: Other information
One important detail: Sections 12 through 15 must be present in the document, but OSHA considers them non-mandatory. That means OSHA won’t enforce the content within those sections, because the information falls under the jurisdiction of other agencies like the EPA or the Department of Transportation. You still need to include the section headings and whatever information is available.
Hazard Identification (Section 2)
Section 2 is where the chemical’s dangers are communicated visually and verbally. It requires specific labeling elements: a signal word (either “Danger” or “Warning”), hazard statements describing the nature of the risk, precautionary statements, and pictograms. Pictograms are diamond-shaped symbols with a black hazard icon on a white background inside a red border. Eight standard symbols exist, covering hazards like flammability, corrosion, toxicity, and environmental danger.
Precedence rules prevent redundant or confusing labels. If “Danger” applies, you cannot also include “Warning.” If the skull-and-crossbones pictogram is used for acute toxicity, the exclamation mark pictogram cannot appear for that same hazard. The same logic applies when the corrosive symbol covers skin or eye irritation, or when the health hazard pictogram covers respiratory sensitization. Each pictogram may appear only once on a label, even if multiple hazard categories call for it.
Hazard statements can be combined to improve readability, as long as all hazards are still communicated. When a statement includes variable information (like naming the specific organs affected), that detail must be filled in rather than left generic.
Composition and Ingredient Disclosure (Section 3)
For single substances, Section 3 requires the chemical name, common names and synonyms, the CAS (Chemical Abstracts Service) number, and information about any impurities or stabilizing additives that contribute to the chemical’s hazard classification.
Mixtures have stricter disclosure rules. You must list the chemical name and exact concentration of every ingredient classified as a health hazard that is present above its concentration limit, or that poses a health risk even below that limit. Exact percentages are the default requirement, but concentration ranges are permitted in three situations: when a trade secret claim is made, when there’s batch-to-batch variation in the product, or when one SDS covers a group of substantially similar mixtures.
Trade Secret Protections
Manufacturers can withhold the specific chemical identity or exact concentration of an ingredient if they claim it as a trade secret. But this protection has limits. The SDS must include a statement acknowledging that information has been withheld, and it must still disclose the hazardous properties, health effects, and applicable exposure limits for the hidden ingredient. You can’t use a trade secret claim to hide the fact that something is dangerous.
To qualify as a legitimate trade secret, the ingredient must genuinely be confidential. OSHA considers factors like how widely known the ingredient already is, what measures the company takes to guard the secret, the ingredient’s competitive value, and how easily a competitor could figure it out independently. Chemicals that are publicly known or obvious from the marketed product itself cannot be claimed as trade secrets.
Physical and Chemical Properties (Section 9)
Section 9 has one of the longest lists of required data points. The SDS must address 18 specific properties:
- Appearance: physical state, color, and odor (including odor threshold)
- Temperature data: melting/freezing point, boiling point or boiling range, flash point, auto-ignition temperature, and decomposition temperature
- Flammability data: flammability rating, and lower/upper explosion or flammability limits
- Chemical behavior: pH, solubility, vapor pressure (including evaporation rate), and the partition coefficient (a measure of how a chemical distributes between water and oil)
- Physical measurements: kinematic viscosity, density and/or relative density, relative vapor density, and particle characteristics
If a property doesn’t apply to the chemical, the SDS should state that rather than leave the field blank. A blank field creates ambiguity about whether the data is unavailable or simply wasn’t included.
EU Requirements Compared to U.S.
The European Union follows the same 16-section structure, but the rules come from REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) rather than OSHA. Annex II of the REACH regulation defines the SDS requirements. The section headings and order are nearly identical, which is the whole point of the GHS framework.
There are practical differences, though. An SDS distributed in the EU must be written in the official language of the member state where the chemical is sold. EU sheets must also be consistent with the chemical safety report prepared under REACH. For substances that require a chemical safety assessment, the SDS may need to include “exposure scenarios” as an annex. These extended SDSs describe the specific conditions under which the manufacturer recommends the chemical be used safely, covering both human health and environmental exposure. This annex requirement has no direct equivalent in the U.S. system.
Section 15 (Regulatory information) also differs in practice. In the EU, it must note whether the substance is subject to authorization or restriction under REACH and whether a chemical safety assessment has been carried out. In the U.S., this section typically references EPA regulations, state-level right-to-know laws, and other federal requirements.
How Employers Must Provide Access
OSHA requires that employees have immediate access to SDSs for every hazardous chemical in their workplace. The standard uses the phrase “readily accessible,” which OSHA interprets as meaning workers can read and refer to the information without delay during their shift.
Employers have flexibility in how they provide this access. Paper binders, computer terminals, or any other system that produces a readable copy on-site all qualify. If you use an electronic system, you need a backup plan. In a power outage or equipment failure, OSHA considers phone-based transmission of hazard information acceptable as a temporary measure, as long as the actual SDS document is delivered to the site as soon as possible. An auxiliary power system, like an uninterruptible power supply, is another acceptable safeguard. The only scenario where a two-hour delay in producing a readable SDS is considered acceptable is when the primary electronic system has failed and two hours is genuinely the fastest possible delivery time.