Acrylonitrile SDS Explained: The Six Sections Buyers and EHS Should Read First

For acrylonitrile, a 16-section safety data sheet functions as a set of interlocking control points for procurement, storage, and emergency response. Buyers and environmental health and safety personnel commonly screen Sections 1 through 6 before accepting a shipment because those sections contain product identity, hazard classification, composition, first-aid, fire-fighting, and release-response data that determine whether the material can be handled safely under existing site conditions. The six read-first sections are Section 1 identification, Section 2 hazard identification, Section 3 composition/information on ingredients, Section 4 first-aid measures, Section 5 fire-fighting measures, and Section 6 accidental release measures. This technical review covers acrylonitrile, CAS 107-13-1, EC 203-466-5, UN 1093, and explains why each section is a procurement or EHS decision point rather than a routine compliance block.

Product identity data in Section 1 of the acrylonitrile SDS should be cross-checked against the purchase order, transport document, and storage permit before unloading. The substance is identified by CAS 107-13-1, EC 203-466-5, and the proper shipping name “Acrylonitrile, stabilized,” with UN number 1093, transport class 3, and packing group I. Section 1 also supplies the supplier name, address, emergency telephone, and recommended use. For polymer-grade acrylonitrile used in ABS, SAN, nitrile rubber, and polyacrylonitrile fibre production, the recommended use should match the site process. A Section 1 that lists a different stabiliser package or a derivative-grade identifier may signal that the shipment is not interchangeable with the qualified incoming raw material. The SDS revision date in Section 1 is a read-first control point because regulatory updates to formulation or classification can occur without a change in trade name. Buyers should reject outdated SDSs that do not reflect the prevailing GHS or REACH text, especially if the site operates under a current ISO 9001:2015 supplier control procedure.

Section 2 as the Primary Hazard Screen

The GHS classification block in Section 2 functions as the primary hazard screen for acrylonitrile because the substance combines a low flash point with acute toxicity, skin sensitisation, eye damage, and chronic endpoints. Commercial SDSs reviewed for monomer-grade acrylonitrile assign Flammable Liquid Category 2 with hazard statement H225; Acute Toxicity Category 3 for oral, dermal, and inhalation routes with H301, H311, and H331; Skin Irritation Category 2 with H315; Eye Damage Category 1 with H318; Skin Sensitisation Category 1B with H317; Carcinogenicity Category 1B with H350; Reproductive Toxicity Category 2 with H361d; Specific Target Organ Toxicity Single Exposure Category 3 with H335; and Hazardous to the Aquatic Environment Chronic 2 with H411. The signal word is Danger. The assigned pictograms normally include the flame, skull and crossbones, corrosion, and health hazard symbols. Buyers read Section 2 to confirm that the supplier has classified the monomer as a flammable liquid and acute toxicant rather than as a lower-hazard intermediate, because an incomplete classification changes warehouse segregation, container labelling, and workplace exposure controls.

Section 2 also carries the label elements required under US 29 CFR 1910.1200 Appendix D and EU REACH Annex II as amended by Commission Regulation (EU) 2020/878. For acrylonitrile, the hazard statement combination is the practical bridge to the substance-specific standard at 29 CFR 1910.1045, which sets a permissible exposure limit of 2 ppm as an 8-hour time-weighted average and a ceiling concentration of 10 ppm for any 15-minute period. An action level of 1 ppm triggers additional exposure monitoring. This linkage matters because Section 2 of the SDS alerts the reader to the acute toxicity classes; the exposure limit data then appears in Section 8, but the hazard classification in Section 2 determines whether the substance-specific OSHA program is activated.

The classification block is also used to set site storage and unloading controls before Section 7 and Section 9 are consulted. A flammable liquid with an acute inhalation toxicity category of 3 cannot be treated as a general solvent. The reader should verify that the SDS shows the skull and crossbones pictogram because that pictogram triggers the requirement for confined-space and tank-car entry controls, medical surveillance, and emergency response planning. In addition, the H statement string ties directly to the need for a written hazard communication program under 29 CFR 1910.1200. Sites receiving acrylonitrile by railcar or ISO tank container also use Section 2 to brief operators on the acute inhalation hazard before connecting transfer lines.

When Section 3 Ingredients Data Drives Specification and Sourcing

Section 3 of an acrylonitrile SDS receives less attention than Section 2, but the composition table controls specification and sourcing for monomer-grade material. Commercial acrylonitrile is stabilised with hydroquinone monomethyl ether, also identified as 4-methoxyphenol, at concentrations reported in Section 3; a common stabiliser range for nitrile rubber and ABS polymer feedstocks is 35–50 ppm MEHQ. This value is not incidental. If the stabiliser concentration is absent or below the lower end, the buyer cannot confirm that the lot will resist exothermic polymerisation during ambient storage or short-term process hold. Section 3 should also state the acrylonitrile concentration, typically above 99% for polymer-grade material, and any trade secret identity claims must comply with the disclosure limits of 29 CFR 1910.1200(i) in the United States or the equivalent REACH Annex II requirement in the EU.

Procurement screening of Section 3 also verifies whether the SDS matches the certificate of analysis. A supplier that lists a broad range without specifying the inhibitory package may be supplying a grade intended for derivative production rather than for direct polymerisation. In such cases, the receiving laboratory should confirm the MEHQ titre by gas chromatography with flame ionisation detection using an internal standard protocol. Published data for the precise MEHQ concentration in every producer's bulk shipment is often limited because the value is producer-specific and appears in the certificate of analysis; the SDS remains the first control document for identifying the inhibitor chemistry. Acrylonitrile itself is subject to reporting under US EPA 40 CFR Part 372 Section 313 and therefore Section 3 may also include a comment that the product is subject to Toxic Release Inventory reporting.

When Section 3 lists the stabiliser only as a generic trade name or omits the concentration, procurement should request the certificate of analysis before unloading. Gas chromatography with flame ionisation detection using a polar capillary column is one method for MEHQ determination; the specific column and internal standard are selected by the receiving laboratory rather than by the SDS. The SDS concentration range remains the first reference because the certificate of analysis is lot-specific and the SDS is the more stable hazard communication document. Buyers using a REACH-registered supplier should confirm that the Section 3 composition data are consistent with the registration dossier and the extended safety data sheet exposure scenarios.

Section 4 first-aid measures for acrylonitrile are organised by route of exposure because the substance is both a volatile acute toxicant and a direct contact irritant. Inhalation exposure is addressed with removal to fresh air, administration of oxygen if breathing is difficult, and immediate medical evaluation. Skin contact is treated by removing contaminated clothing and washing with soap and water; eye contact requires continuous rinsing with water for at least 15 minutes and urgent ophthalmologic assessment. Ingestion emergencies typically state that vomiting is not to be induced and that the mouth should be rinsed only. The first-aid block is not a substitute for a site-specific medical response plan, but EHS reviewers compare it against the site's emergency shower, eyewash station, and cyanide-aware response arrangements. Emergency eyewash and shower equipment should conform to ANSI/ISEA Z358.1-2014; Section 4 indicates the required irrigation time, while Section 1 and Section 2 establish the need for the equipment.

Because acrylonitrile can liberate cyanide through metabolic pathways, some supplier SDSs contain references to cyanide antidote therapy under medical supervision; however, the exact antidote protocol is jurisdiction-dependent and is limited to trained medical responders. EHS personnel should not extract Section 4 alone for worker training. The section must be read alongside the exposure controls in Section 8, the personal protective equipment requirements, and the medical surveillance provisions of 29 CFR 1910.1045 for employees exposed above the action level. In practice, first-aid data is one of the six read-first sections because it determines whether an incident will be handled as a simple splash or as a possible acute toxic exposure with delayed systemic effects.

Why Section 5 Fire-Fighting Measures Require Alcohol-Resistant Media

Fire-fighting decisions for acrylonitrile pivot on the liquid's low flash point and wide flammability range. Section 5 of a compliant 16-section SDS lists the substance's fire parameters that are relevant to fire suppression: closed-cup flash point approximately -1 °C, boiling point 77.3 °C, lower explosive limit 3.0 vol%, upper explosive limit 17.0 vol%, autoignition temperature near 481 °C, and vapour density approximately 1.83 relative to air. Under NFPA 30 classification, acrylonitrile falls into Class IB because the flash point is below 22.8 °C and the boiling point is above 37.8 °C. This requires storage in grounded and bonded containers with vapour-tight closures, remote from oxidisers and acids, and with emergency ventilation designed for flammable vapour service.

The fire-fighting media named in Section 5 are selected to avoid spreading the liquid. Dry chemical, carbon dioxide, and alcohol-resistant foam are standard; water spray is reserved for cooling exposed drums, tanks, and piping rather than for direct extinguishment. A direct water jet is contraindicated because it can disperse the monomer and increase vapour generation. Section 5 also carries the polymerisation warning: if acrylonitrile is heated above ambient storage conditions, the inhibitor can be consumed and a runaway exothermic polymerisation can rupture closed containers. Fire brigades use water from maximum distance and wear self-contained breathing apparatus with chemical-protective clothing. Buyers read Section 5 because the fire control data interact with warehouse sprinkler design, heat release assumptions, and the site's fire pre-plan; a monomer that is both Class IB flammable and toxic requires a different suppression response than an ordinary flammable solvent without the same acute inhalation hazard.

Release response for acrylonitrile is governed by the same vapour density and low exposure limits that make Section 2 an acute-toxicity screen. Section 6 of the SDS requires elimination of all ignition sources, isolation of the spill area, and ventilation with explosion-proof equipment before any containment action. Because acrylonitrile vapour is heavier than air and can travel to remote ignition sources, EHS reviewers compare the Section 6 instructions against the site's classified electrical installations and floor-level ventilation. Spills should be contained with inert absorbents such as vermiculite or dry sand, transferred to closed, properly labelled containers, and segregated from acids or alkalis that can accelerate polymerisation. Releases must not be flushed to sanitary or storm drains without first checking the facility's wastewater permits and the aquatic hazard classification in Section 2.

Section 6 also specifies personal protective equipment for spill response. In the United States, spill responders must be equipped to operate below the substance-specific exposure limits of 29 CFR 1910.1045, which are lower than the generic thresholds for many other monomers. Air-purifying respirators are not appropriate for unknown concentrations; self-contained breathing apparatus is required where acrylonitrile vapour may exceed the ceiling concentration of 10 ppm or where oxygen concentration is below 19.5%. The same section directs the responder to use chemical-protective gloves tested to EN 374 or ASTM F739 for acrylonitrile permeation, chemical splash goggles, and flame-resistant outer clothing. Because Section 6 is emergency-oriented, it does not repeat the full exposure control logic of Section 8; instead, it functions as a standalone containment and spill-response checklist for high-risk tasks.