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Safety Data Sheet term · Glossary

Section 9: Physical & Chemical Properties

Verified vs OSHA sources · 2026-10-05

The SDS section that lists the chemical's measurable physical and chemical properties — appearance, odor, pH, melting/boiling point, flash point, flammable (explosive) limits, vapor pressure and density, relative density, solubility, auto-ignition and decomposition temperatures, and viscosity. These numbers underpin the hazard classification and tell you how the chemical will behave.

29 CFR 1910.1200 App D

Also known as: SDS Section 9, physical properties section

Section 9: Physical & Chemical Properties at a glance

  • Lists the substance's measurable physical/chemical properties.
  • Flash point and flammable limits (LEL/UEL) drive the fire-hazard classification.
  • Vapor pressure and density predict how vapors behave if released.
  • Kinematic viscosity is used to judge aspiration hazard for hydrocarbons.

In plain English

The “data sheet” page — the hard numbers. Flash point, boiling point, vapor pressure, pH, density, how well it dissolves. These properties explain why a chemical is flammable, how fast it evaporates, and how it'll act if released.

What the source says, in summary

Section 9, Physical and chemical properties: appearance; odor; odor threshold; pH; melting/freezing point; initial boiling point; flash point; evaporation rate; flammability; upper/lower flammability or explosive limits; vapor pressure; vapor density; relative density; solubility; partition coefficient; auto-ignition temperature; decomposition temperature; and viscosity.
29 CFR 1910.1200 App D (Section 9)Summarized, not quoted: read the source for its operative wording.

In context

A concept tied to the 16-section Safety Data Sheet required for every hazardous chemical under OSHA's Hazard Communication Standard, 29 CFR 1910.1200(g).

29 CFR 1910.1200(g)

Where this is written in OSHA's rules

Example

Acetone's Section 9 shows a flash point of about −20 °C, a boiling point of 56 °C, and high vapor pressure — numbers that explain its Flammable Liquid Category 2 classification and why its vapors accumulate quickly at room temperature.

Why it matters

Section 9 is the objective data behind every hazard call — a wrong flash point or vapor pressure can lead to the wrong flammable category and the wrong storage. Industrial hygienists and engineers use these properties to design ventilation, predict vapor behavior, and plan spill response.

Flash point vs. auto-ignition temperature

Both appear in Section 9 but mean different things. Flash point is the lowest temperature at which vapors ignite with a spark or flame. Auto-ignition temperature is where the chemical ignites on its own, with no ignition source — and it's much higher. Confusing the two leads to unsafe assumptions about ignition risk.

Key Section 9 properties and what they tell you

PropertyWhy it matters
Flash pointHow easily the liquid ignites → flammable category
Flammable limits (LEL/UEL)The ignitable vapor range in air
Vapor pressure / densityHow fast it evaporates; whether vapors sink or rise
Kinematic viscosityAspiration hazard for hydrocarbons (≤ 20.5 mm²/s)

Section 9: Physical & Chemical Properties: frequently asked questions

What is in Section 9 of an SDS?
The chemical's measurable physical and chemical properties — appearance, odor, pH, flash point, boiling point, flammable limits, vapor pressure and density, solubility, auto-ignition and decomposition temperatures, and viscosity.
Where is the flash point on an SDS?
In Section 9 (Physical and chemical properties). The flash point, along with boiling point and flammable limits, underpins the flammable-liquid classification shown in Section 2.
Why are these properties important?
They determine the hazard classification and how the chemical behaves — how easily it ignites, how fast it evaporates, and how its vapors move — which drives storage, ventilation, and emergency response decisions.

Related terms

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Governing OSHA standards

More SDS terms

Safety Data Sheet (SDS)

A standardized 16-section document the chemical manufacturer, importer, or distributor must provide for every hazardous chemical, detailing its hazards, safe handling, storage, exposure controls, first aid, and emergency information. Its content and order are set by 29 CFR 1910.1200(g) and Appendix D; it replaced the unstandardized MSDS under GHS alignment.

Readily Accessible

The OSHA requirement that safety data sheets be readily accessible to employees during each work shift, in their work areas (29 CFR 1910.1200(g)(8); adopted for construction by 1926.59). “Readily accessible” means without barriers or unreasonable delay — electronic access is allowed, but only with reliable backup for power or system failures and no obstacle between the worker and the SDS.

Section 1: Identification

The first section of a Safety Data Sheet. It identifies the chemical and who's responsible for it: the product identifier (matching the label), recommended use and restrictions, the manufacturer/importer's name, address, and phone, and — critically — an emergency phone number. It's the section a responder reads first to confirm they have the right SDS.

Section 2: Hazard Identification

The SDS section that states what's dangerous about the chemical: its GHS hazard classification (each hazard class and category), all the required label elements (pictograms, signal word, hazard statements, precautionary statements), and any hazards not otherwise classified (HNOC). It's the fastest read for “how could this hurt me?”

Section 3: Composition / Information on Ingredients

The SDS section that discloses what the chemical is made of: the chemical name, common names/synonyms, CAS number, and concentration (or concentration range) of the substance or of each hazardous ingredient in a mixture. Any ingredient that contributes to a classified hazard must be listed, subject to limited trade-secret protection.

Section 4: First-Aid Measures

The SDS section that tells you what to do if someone is exposed. It gives first-aid instructions broken out by route of exposure — inhalation, skin, eye, and ingestion — plus the most important symptoms (immediate and delayed) and any indication of the need for immediate medical attention or special treatment. It's the section to open in a medical emergency.

Section 5: Fire-Fighting Measures

The SDS section written for anyone fighting a fire involving the chemical. It lists suitable and unsuitable extinguishing media, the specific hazards the chemical creates in a fire (toxic combustion products, explosion risk, reactivity), and the special protective equipment and precautions firefighters need. It's a key reference for the fire department's pre-planning.

Section 6: Accidental Release Measures

The SDS section that tells you how to handle a spill or leak. It covers personal precautions, protective equipment, and emergency procedures (protecting people first), environmental precautions (keeping it out of drains and waterways), and the methods and materials for containment and cleanup. It's the spill-response playbook for the chemical.

Sources & verification

Reviewed by HazComFast against eCFR, OSHA.gov, NIOSH, and the Federal Register. Last reviewed 2026-10-05. This glossary is general information, not legal advice; OSHA State-Plan states (e.g. California, Michigan) may adopt stricter requirements.

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