How to Read a Safety Data Sheet (SDS): A Complete Guide

What is a Safety Data Sheet?

A Safety Data Sheet (SDS) is a detailed document that provides comprehensive information about a hazardous chemical. Under OSHA's Hazard Communication Standard (29 CFR 1910.1200), manufacturers must provide an SDS for every hazardous product, and employers must ensure workers can access these documents.

Understanding how to read an SDS quickly is critical — especially in emergencies when seconds matter. This guide walks you through all 16 sections and shows you where to find the most important information. But before you read one, it helps to know whether a given product even requires one — so we start there, then move through the sheet section by section. One thing this guide assumes is that the sheet is in English, which is what 1910.1200(g)(2) requires; if your crew reads Spanish, the training, not the sheet, is what has to change.

When Do You Actually Need an SDS?

You need an SDS for every hazardous chemical employees may be exposed to (1910.1200(g)(1)) — but not for everything on site. OSHA's scope exempts several things, and the exemptions are narrower than most people assume:

• Consumer products used like a consumer would. A product used for its intended purpose, with a duration and frequency of exposure no greater than a normal consumer's, is exempt (1910.1200(b)(6)(ix)). This turns on how much and how often — not where you bought it. A dab of hardware-store adhesive at a desk is exempt; running cases of that same adhesive across a shift far exceeds consumer exposure, so you need the SDS and training.
• Articles. A manufactured item formed to a specific shape, whose use depends on that shape, that releases no more than trace amounts of a hazardous chemical and poses no physical or health risk, is an "article" (defined in 1910.1200(c)) and is exempt (1910.1200(b)(6)(v)). A steel beam or a finished countertop is an article; a bag of powder or a pail of liquid is not.
• Food, drugs, cosmetics, and tobacco intended for employees' personal consumption are exempt (1910.1200(b)(6)(vi)–(viii)).
• Also outside the SDS duty: hazardous waste regulated under RCRA, and certain wood/wood products (1910.1200(b)).

When in doubt, keep the SDS — the cost of an extra sheet is nothing next to a "no SDS for a chemical in use" citation. For the full twelve-category exemption list, the (b)(5) labeling-only carve-outs, and the gray-area calls (wood dust, processed articles, waste), see Does every chemical need an SDS?.

What if a supplier never sent the SDS?

If a chemical arrives without an SDS, you are not off the hook — and neither is the supplier. Under 1910.1200(g)(6)(iii)–(iv), you must obtain the SDS from the manufacturer or importer as soon as possible, and the manufacturer must provide one upon request. Put the request in writing and keep a copy; documented "reasonable diligence" is what shows good faith if the sheet is still missing when an inspector asks. If the supplier stonewalls, contact your nearest OSHA office. For the full process and a copy-paste request letter, see Supplier won't provide an SDS? What to do.

SDS at a Glance: Quick Reference Table

Section 1: Identification

This section tells you exactly what product you're dealing with:

• Product identifier: The product name or code (must match the container label exactly; the identifier is defined in 29 CFR 1910.1200(c))
• Manufacturer information: Company name, address, phone, and 24-hour emergency phone number
• Recommended use: What the product is intended for
• Restrictions on use: Known unsuitable applications

Pro tip: Always verify the SDS matches your product by checking the product identifier against your container label. Different formulations of the "same" product (e.g., different concentrations) will have different SDSs.

Section 2: Hazard Identification (THE MOST IMPORTANT)

This is the section you'll reference most often. It is the executive summary of everything dangerous about the chemical.

What you'll find:

The label on the shipped container carries the same signal word, pictograms and statements, under 29 CFR 1910.1200(f)(1).

Understanding Signal Words:

• "Danger" = More severe hazard (e.g., fatal if swallowed, causes severe burns)
• "Warning" = Less severe hazard (e.g., harmful if swallowed, causes irritation)
• If no signal word appears, the chemical may not meet GHS classification thresholds but could still be hazardous

Understanding H-Codes (Hazard Statements):

• H2xx = Physical hazards (fire, explosion, oxidizing)
• H3xx = Health hazards (toxicity, irritation, sensitization)
• H4xx = Environmental hazards (aquatic toxicity)

Section 3: Composition/Information on Ingredients

Lists the hazardous ingredients with CAS numbers and concentration ranges. This is essential for:

• Medical treatment decisions — emergency responders need to know exactly what chemicals are involved
• Exposure monitoring — matching air sampling results to specific substances
• Understanding chemical interactions — checking compatibility with other chemicals on-site
• Regulatory reporting — Tier II, TRI, and other EPA reporting thresholds

Key data points:

• Chemical name and CAS number for each hazardous ingredient
• Concentration range (e.g., 10-25%) — exact percentages may be trade secrets, in which case the SDS must give one of the prescribed ranges of 29 CFR 1910.1200(i)(1)(iv)
• Any impurities or stabilizing additives that contribute to hazards

Use our Chemical Inventory Template to look up detailed safety information on specific chemicals by CAS number.

Section 4: First Aid Measures

Critical in emergencies. Organized by exposure route:

Best practice: Print Section 4 information and post it at chemical storage areas. In an emergency, workers need this information in seconds, not minutes. On a construction site, first aid and eyewash duties sit in 29 CFR 1926.50, including quick-drench or eyewash facilities where corrosives are present (29 CFR 1926.50(g)).

Important symptoms and effects are also listed here — what the victim may experience (dizziness, nausea, burns) so responders know what to watch for.

Section 5: Fire-Fighting Measures

Information for fire response teams:

• Suitable extinguishing media — Some chemicals react violently with water. This section tells you what to use instead (CO₂, dry chemical, foam).
• Unsuitable media — What NOT to use (e.g., "Do NOT use water stream on this chemical")
• Hazardous combustion products — What toxic gases may be released when the chemical burns (CO, HCl, NOx, etc.)
• Special protective equipment for firefighters — Beyond standard turnout gear

On a construction site, the employer's fire protection program and extinguishers fall under 29 CFR 1926.150(a)(1).

Section 6: Accidental Release Measures

Your spill response playbook:

• Personal precautions — What PPE to wear during cleanup
• Environmental precautions — Preventing drainage into sewers or waterways
• Containment methods — Dikes, absorbents, neutralizers
• Cleanup methods — How to safely clean up and dispose of spilled material

Construction context: On jobsites, spills near storm drains can trigger EPA violations in addition to OSHA citations. Know your spill response procedures before chemicals arrive on-site; a crew that responds to releases beyond incidental cleanup is under HAZWOPER's emergency-response rules (29 CFR 1926.65(q) in construction, 29 CFR 1910.120(q) in general industry).

Section 7: Handling and Storage

Day-to-day guidance for safe use:

• Safe handling practices — Ventilation, grounding, hygiene measures
• Conditions for safe storage — Temperature range, incompatible materials, container type
• Specific end uses — Any sector-specific guidance

Key storage requirements to note:

• Maximum storage temperature
• Incompatible materials (what NOT to store nearby)
• Required ventilation
• Whether the container must be grounded

On a construction site, flammable and combustible liquid storage is governed by 29 CFR 1926.152.

→ Check compatibility: Chemical Compatibility Matrix

Section 8: Exposure Controls/Personal Protection

Another critical section for daily operations:

Occupational Exposure Limits

PPE Requirements

This section specifies exactly what protection you need:

• Respiratory: Type of respirator, cartridge type, APF (Assigned Protection Factor); the respirator program itself is 29 CFR 1910.134, applied to construction by 29 CFR 1926.103
• Hands: Glove material (nitrile, neoprene, butyl), thickness, breakthrough time
• Eyes: Safety glasses vs. goggles vs. face shield (29 CFR 1926.102(a)(1) on construction sites)
• Body: Apron, coveralls, boot covers (provided and used wherever chemical hazards require them, 29 CFR 1926.95(a))

→ Get PPE recommendations: PPE Selector Tool → Create compliant labels: GHS Label Generator

Section 9: Physical and Chemical Properties

Technical data for risk assessment:

Important: If the odor threshold is above the PEL, you cannot rely on smell to detect dangerous concentrations. You need air monitoring.

Section 10: Stability and Reactivity

Tells you what conditions or materials to avoid:

• Chemical stability — Is it stable under normal conditions?
• Conditions to avoid — Heat, sunlight, moisture, friction
• Incompatible materials — What it reacts with (acids, bases, oxidizers)
• Hazardous decomposition products — What forms when it breaks down

Construction relevance: Temperature extremes on jobsites (hot rooftops, cold basements) can destabilize certain chemicals. Check this section when storing chemicals in non-climate-controlled areas.

Section 11: Toxicological Information

Detailed health effect data:

• Acute toxicity values — LD₅₀ (lethal dose, 50% of test population) and LC₅₀ (lethal concentration)
• Routes of exposure — Oral, dermal, inhalation
• Chronic effects — Carcinogenicity, mutagenicity, reproductive toxicity
• IARC/NTP classifications — Whether the chemical is a known or suspected carcinogen

Sections 12-15: Environmental, Disposal, Transport, Regulatory

These sections are regulated by agencies other than OSHA but are still part of the standardized SDS format:

Section 16: Other Information

Revision history and important context:

• SDS revision date — Is this SDS current? Check against GHS Rev 7 deadlines
• Version number — Track which version you have
• Abbreviations — Definitions for technical terms used throughout
• Training information — Additional safety training recommendations

Worked Example: An Annotated SDS (Acetone)

Theory is easier to hold against a real sheet. Below is an illustrative SDS for acetone — one of the most common jobsite solvents — annotated to show what to check in each section that matters most. The hazard data is real and verified (ECHA harmonised classification for acetone, CAS 67-64-1, and OSHA's Table Z-1 PEL); it is a teaching example, not a specific manufacturer's document.

How to spot a stale or non-compliant SDS

Reading an SDS is only useful if the sheet is a good one. Five tells flag a sheet you shouldn't trust:

1. It isn't in the 16-section GHS order. A free-format sheet, or one still labeled "MSDS," predates the 2012 rule. OSHA's July 27, 2015 letter treats an MSDS for a product received before June 1, 2015 as compliant until the supplier issues an updated SDS; after that, ask for the 16-section sheet that 29 CFR 1910.1200(g)(2) requires.
2. No revision date in Section 16. A missing preparation/revision date is the classic sign of a stale library — you can't tell whether it reflects the chemical's current classification.
3. Old "R/S phrases" instead of H/P codes. European R/S phrases, or NFPA-only ratings, in place of GHS H- and P- statements mean the sheet predates GHS alignment (or is a foreign format never adapted for OSHA).
4. Section 8 PELs that don't match the current OSHA limit. An SDS can lag a rulemaking — a silica sheet still citing an old nuisance-dust limit rather than the 50 µg/m³ construction PEL (1926.1153), for instance. Cross-check Section 8 against the current OSHA Table Z value.
5. The product identifier doesn't match your container label. Different formulation, different concentration, or simply the wrong sheet — Section 1 must match the label exactly.

Any one of these is a reason to request a fresh SDS from the manufacturer under 1910.1200(g) before you rely on the sheet.

Quick Reference: Finding Key Information Fast

In an emergency (seconds count):

• Sections 2, 4, 5, 6

For daily PPE decisions:

• Section 8

Setting up a new chemical storage area:

• Sections 7, 9, 10

For regulatory reporting:

• Sections 3, 12, 13, 15

Before a new chemical arrives on-site:

• Sections 1, 2, 3, 7, 8 (minimum)

Common SDS Mistakes to Avoid

1. Using an outdated SDS — Check the revision date in Section 16. Any SDS not updated for GHS Rev 7 by the manufacturer's deadline may be non-compliant.
2. Wrong SDS for the product — Different concentrations or formulations have different SDSs. Always match the product identifier.
3. Relying on generic safety rules — Each chemical has specific hazards. "Wear gloves" isn't enough — the SDS specifies the type of gloves.
4. Ignoring Section 10 — Incompatible materials can react to cause fires, toxic gases or explosions; Section 10 lists them.
5. Not training workers on how to read SDSs — Access is useless if workers can't interpret the information.

Stay Audit-Ready: SDS Access and Inspection Prep

OSHA inspectors will ask how employees access SDSs during their shift — the "readily accessible" test of 29 CFR 1910.1200(g)(8). They will:

1. Ask an employee to retrieve an SDS for a specific chemical; OSHA's 2015 HazCom directive (CPL 02-02-079, now archived) told inspectors to check that workers know how to access SDSs
2. Verify the SDS is current and matches the product on-site
3. Check that the employee understands key sections

For a full inspection checklist and free tools, see How to Prepare for an OSHA HazCom Inspection. Use the Chemical Inventory Template and the gap-analysis method to keep every product matched to a current SDS.

Conclusion

Reading an SDS doesn't have to be overwhelming. Focus on the sections relevant to your immediate needs, and always verify you have the most current version. The 16-section format is designed so that the most critical information (hazards, first aid, PPE) comes first.

With HazComFast, your jobsite's SDS load onto the phone on their own, so Section 4 is there in the basement or the tunnel where you need it.

The standard, tools & related reading

• The standard: Hazard Communication — 29 CFR 1910.1200 · SDS Management hub
• Manage your library: SDS Gap Analyzer · SDS QR Code Generator · Chemical Inventory Template
• Related guides: SDS: 16 Sections Explained · GHS Pictograms Explained · SDS Management Best Practices · Are Digital SDS Legal?
• 2026 OSHA penalty schedule · penalties by state