Hazardous chemicals classification and identification assessment is an essential compliance procedure that determines whether a substance or mixture meets the hazard criteria of the UN GHS framework, China's Catalogue of Hazardous Chemicals, and international dangerous goods transport regulations. By combining compositional analysis, physicochemical testing and expert data evaluation, accredited third-party laboratories help chemical manufacturers, importers and downstream users confirm regulatory status, produce compliant safety data sheets and labels, and control risks throughout storage, transport and use. This article provides a comprehensive technical guide covering the scope, sample requirements, test items, methods, standards and practical applications of hazardous chemicals classification and identification assessment.
Technical Overview
Hazardous chemicals classification and identification assessment is a systematic technical process used to determine the hazard classes and categories of chemicals according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and its national implementations, and to establish whether a product falls under regulatory control as a hazardous chemical or dangerous good. The assessment integrates documentary review, compositional identification, experimental testing where data gaps exist, and expert evaluation against classification criteria. The final output supports safety data sheet (SDS) authoring, GHS labeling, transport classification, and registration or licensing submissions.
Regulatory Basis
- The UN GHS "Purple Book" and the UN Model Regulations on the Transport of Dangerous Goods, including the UN Manual of Tests and Criteria.
- China: Regulations on the Safety Management of Hazardous Chemicals (State Council Decree No. 591), the Catalogue of Hazardous Chemicals (2015 edition), the GB 30000 series of classification standards, GB 6944 and GB 12268 for dangerous goods.
- European Union: Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging (CLP) of substances and mixtures.
- United States: OSHA Hazard Communication Standard 2012 (29 CFR 1910.1200).
- Japan: JIS Z 7252 for GHS classification and JIS Z 7253 for labels and safety data sheets.
- Modal transport codes: IMDG Code for sea, IATA Dangerous Goods Regulations for air, and ADR for road.
GHS Hazard Classes Covered
- Physical hazards: explosives, flammable gases, aerosols, oxidizing gases, gases under pressure, flammable liquids and solids, self-reactive substances, pyrophoric liquids and solids, self-heating substances, substances which in contact with water emit flammable gases, oxidizing liquids and solids, organic peroxides, metal corrosives and desensitized explosives.
- Health hazards: acute toxicity, skin corrosion or irritation, serious eye damage or eye irritation, respiratory and skin sensitization, germ cell mutagenicity, carcinogenicity, reproductive toxicity, specific target organ toxicity (single and repeated exposure) and aspiration hazard.
- Environmental hazards: hazardous to the aquatic environment and hazardous to the ozone layer.
Assessment Workflow
- Documentary review of composition, CAS numbers, existing test reports and available SDSs.
- Preliminary screening against the Catalogue of Hazardous Chemicals and dangerous goods lists.
- Compositional identification and verification of the sample in the laboratory.
- Experimental testing to fill data gaps in physical, health and environmental endpoints.
- Classification against GHS criteria, cut-off values and concentration limits.
- Determination of hazardous chemical status and dangerous goods classification, including UN number and packing group where applicable.
- Issuance of the identification and classification assessment report with SDS and label recommendations.
Testing Samples
Pure Substances and Raw Materials
Industrial raw materials, chemical intermediates, monomers, catalysts, solvents and reagents are assessed to confirm their hazard profile and regulatory status before production, trading or import. For listed substances, classification can often be completed through literature evaluation; for unlisted or data-poor substances, experimental testing is required.
Mixtures and Formulated Products
Coatings, inks, adhesives, sealants, dyes, pigments, lubricants, cleaning agents, surfactants, agrochemical formulations and specialty chemical blends are evaluated using component data, bridging principles and calculation methods, supplemented by targeted testing of the mixture itself where the classification cannot be derived by calculation.
Unknown and Unlabeled Chemicals
Unlabeled containers, aged or degraded materials, research byproducts, seized goods and chemical wastes are subjected to full compositional screening and hazard identification to determine safe handling, storage and disposal requirements.
Sample Requirements
Typical sample quantities range from 50 g to 1 kg (or mL) depending on the test matrix. Samples should be supplied in clean, sealed, chemically compatible containers; air- and moisture-sensitive materials should be packaged under inert atmosphere. A composition sheet, existing SDS or available physical property data should accompany the sample whenever possible to reduce testing scope and turnaround time.
Testing Items
Physical Hazard Tests
- Flash point (closed cup and open cup), initial boiling point and fire point.
- Auto-ignition temperature and flammability limits (LEL and UEL).
- Flammability of gases, liquids and solids; sustained combustibility.
- Oxidizing properties of solids and liquids.
- Explosive properties, self-reactivity and organic peroxide properties.
- Pyrophoricity, self-heating behavior and emission of flammable gases in contact with water.
- Corrosivity to metals, thermal stability, viscosity, pH and physical state determination.
Health Hazard Assessments
- Acute toxicity via oral, dermal and inhalation routes (ATE determination).
- Skin corrosion or irritation and serious eye damage or irritation, preferably using validated in vitro methods.
- Respiratory and skin sensitization screening, including in chemico and in vitro approaches.
- Germ cell mutagenicity screening (such as the bacterial reverse mutation test) and genotoxicity indicators.
- Evaluation of carcinogenicity, reproductive toxicity, specific target organ toxicity and aspiration hazard based on data review and structure-based assessment where testing is not justified.
Environmental Hazard Tests
- Acute and chronic aquatic toxicity testing on fish, invertebrates and algae.
- Ready biodegradability and hydrolysis studies.
- Bioaccumulation potential (octanol-water partition coefficient, log Kow).
Composition and Structural Identification
- Qualitative and quantitative composition analysis by GC-MS, LC-MS/MS, HPLC, GC, ion chromatography and ICP-OES/MS.
- Structural confirmation by FTIR, Raman, NMR, XRF and XRD where required.
- Purity and impurity profiling, water content, VOC content and restricted substance screening.
Deliverables
- GHS classification table with hazard classes, categories, pictograms, signal words and hazard statements.
- Determination of whether the product is a hazardous chemical under the applicable catalogue and category criteria.
- Dangerous goods classification results, including UN number, proper shipping name, hazard class or division and packing group.
- Recommendations for SDS preparation, labeling, packaging and storage.
Testing Methods
Physicochemical Test Methods and Standards
- Flash point, closed cup: ISO 2719, ASTM D93, GB/T 261; rapid equilibrium closed cup: ISO 3679, ASTM D3278, GB/T 5208.
- Flash point and fire point, open cup: ISO 2592, ASTM D92, GB/T 267.
- Auto-ignition temperature: GB/T 5332, ASTM E659, EN 14522.
- Explosion limits of gases and vapors: GB/T 12474, ASTM E681; flammability of gases: ISO 10156.
- Boiling point: ISO 4626, ASTM D86, GB/T 616; viscosity: ISO 3104, ASTM D445, GB/T 265.
- Flammability of solids (burning rate), pyrophoric solids and liquids, self-heating and water-reactive substances: UN Manual of Tests and Criteria Tests N.1 to N.5.
- Explosive properties, self-reactive substances and organic peroxides: UN Manual of Tests and Criteria Test Series 1 to 8.
- Oxidizing liquids and solids: UN Manual of Tests and Criteria Tests O.1, O.2 and O.3.
- Corrosion to metals: UN Manual of Tests and Criteria Section 37; thermal stability screening: ASTM E537 and ISO 11357 (DSC).
Health and Environmental Test Guidelines
- Acute oral toxicity: OECD Test Guidelines 420, 423 and 425; acute dermal and inhalation toxicity: OECD 402, 403 and 436.
- In vitro skin corrosion and irritation: OECD 431, 430 and 439; in vitro eye irritation: OECD 492.
- Skin sensitization: OECD 429 and the OECD 442 series of non-animal methods.
- Genotoxicity screening: OECD 471 (bacterial reverse mutation test), OECD 473 and 474.
- Aquatic toxicity: OECD 201, 202 and 203, with ISO 6341 and ISO 8692 as reference methods; biodegradability: OECD 301 series, OECD 310, ISO 14593 and ISO 9439.
Classification and Documentation Standards
- China GHS classification: GB 30000.2 to GB 30000.29 and GB 13690.
- Dangerous goods: GB 6944 (classification and code), GB 12268 (list of dangerous goods) and GB 190 (package labels).
- SDS: GB/T 16483 and GB/T 17519; chemical labels: GB 15258; Japan: JIS Z 7252 and JIS Z 7253.
- EU CLP Regulation (EC) No 1272/2008 and UN Model Regulations for cross-market classification.
Data Evaluation Strategies
- Weight-of-evidence approach combining existing data, literature and structure-based assessment to minimize animal testing.
- Read-across and QSAR-based estimation supported by expert judgment.
- Bridging principles for mixtures, including dilution, batching, interpolation and substantially-similar-mixture methods.
- Additivity and calculation formulas with generic and specific concentration limits for classifying mixtures from component data.
Applications
Regulatory Registration and Licensing
Assessment reports are used to support hazardous chemicals registration, production and business licensing, safe-use filings and new chemical substance notifications in China and other jurisdictions. They also underpin responses to regulatory inquiries during inspections and post-market surveillance.
Import, Export and Transport Compliance
Dangerous goods classification results enable correct assignment of UN numbers, proper shipping names and packing groups, supporting declarations under the IMDG Code, IATA Dangerous Goods Regulations and ADR, and facilitating smooth customs clearance and carrier acceptance.
SDS and Label Compliance
GHS classification outcomes feed directly into sixteen-section SDSs and compliant labels for target markets, ensuring that hazard communication elements, precautionary statements and pictograms meet the requirements of each jurisdiction.
Product Development and EHS Management
Classification data guide the selection of safer raw materials and formulations, inform storage segregation and fire protection design, support emergency response planning and risk assessments, and strengthen corporate EHS and product stewardship programs.
FAQ
What is the difference between hazardous chemicals and dangerous goods?
Hazardous chemicals refer to substances and mixtures controlled under chemicals safety management regulations based on GHS hazard criteria, while dangerous goods are goods classified for transport under the UN Model Regulations into nine hazard classes. The two systems overlap but are not identical: some products are hazardous chemicals without being dangerous goods, and vice versa, so both determinations may be required.
How is it determined whether a product is a hazardous chemical in China?
The product is first screened against the Catalogue of Hazardous Chemicals. If it is not listed, a hazard classification is performed against the criteria referenced by the catalogue; a chemical that is not in the catalogue but meets the classification criteria is still managed as a hazardous chemical. The assessment report documents this determination.
Do mixtures need to be fully tested?
No. Where reliable component data exist, mixtures are classified using cut-off values, concentration limits, calculation formulas and bridging principles. Laboratory testing of the mixture itself is only required when classification cannot be derived reliably from component data, which significantly reduces cost and animal use.
How long does an assessment take?
A data-based identification and classification assessment for a well-characterized product typically takes five to ten working days. Projects involving experimental testing, such as oxidizing properties or self-heating tests under the UN Manual of Tests and Criteria, may require two to eight weeks depending on the test matrix.
Can the report be used for official submissions?
Yes. Reports issued by accredited third-party laboratories, for example those holding CMA and CNAS accreditation, are recognized for hazardous chemicals registration, licensing, customs and transport documentation purposes, provided the testing methods and classification standards applicable to the target market are applied.