New chemical substance hazard testing is the scientific foundation for registering chemicals that are not yet listed on the Inventory of Existing Chemical Substances in China, ensuring that physicochemical, health, and environmental hazards are fully characterized before manufacture or import. Guided by OECD Test Guidelines, national GB/T standards, and GLP quality principles, this testing supports hazard classification, risk assessment, and regulatory compliance under China's environmental registration framework. This article explains the regulatory background, sample requirements, core test items, standard methods, practical applications, and frequently asked questions for laboratories, manufacturers, and importers.
Technical Overview
In China, any chemical substance that is not listed on the Inventory of Existing Chemical Substances of China (IECSC) is defined as a new chemical substance and must undergo environmental management registration before it is manufactured or imported. The governing regulation is the Measures for the Environmental Management Registration of New Chemical Substances, issued by the Ministry of Ecology and Environment (MEE Order No. 12), which entered into force on January 1, 2021. The regulation establishes three compliance tracks: record-filing for qualifying research and development activities, simple registration generally applicable to annual volumes below one tonne, and regular registration for volumes of one tonne per year or greater.
Hazard testing is the technical core of every registration dossier. Its purpose is to generate reliable data on the intrinsic properties of the substance so that registrants and the competent authority can classify hazards, evaluate persistence, bioaccumulation and toxicity (PBT) concerns, conduct exposure and risk assessment, and define appropriate risk control measures. Data requirements scale with the annual tonnage band, with broader datasets expected as production or import volumes increase into the 1–10, 10–100, and greater than 100 tonne per year ranges.
Testing must be performed using internationally recognized methods, primarily the OECD Guidelines for the Testing of Chemicals together with their adopted Chinese GB/T counterparts, and study data intended for registration must be generated in compliance with the OECD Principles of Good Laboratory Practice (GLP). Data produced in OECD Mutual Acceptance of Data (MAD) adherent jurisdictions are generally accepted, while domestic laboratories must satisfy the corresponding national GLP requirements. Where testing is not scientifically justified, alternatives such as read-across, chemical category approaches, and validated (Q)SAR predictions may be used with adequate technical documentation.
Testing Samples
Pure Substances and Technical-Grade Products
The test sample should be representative of the substance intended for commercial manufacture or import. Typically one or more production batches are supplied with a certificate of analysis stating purity, impurity profile, water content, and composition of additives where applicable. For physicochemical endpoints, a purity of 98 percent or higher is generally recommended; for ecotoxicological studies, purities of at least 80–90 percent are commonly acceptable provided the impurities are characterized. Consistency between the tested sample and the registered substance identity is a key element of technical review.
Polymers, Mixtures, and Substances of Unknown or Variable Composition
Polymeric new substances are assessed for eligibility as polymers of low concern based on number-average molecular weight, residual monomer content, reactive functional groups, and solubility behavior. When a polymer qualifies, testing may be reduced or redirected toward the constituent monomers and additives. For multi-constituent substances and UVCBs, a documented sampling plan is required, and poorly water-soluble or volatile samples may require water-accommodated fractions (WAF) or sealed test designs to maintain meaningful exposure concentrations.
Sample Quantity, Packaging, and Stability
Required quantities depend on the endpoint portfolio: physicochemical studies typically consume grams to tens of grams per endpoint, aquatic toxicity studies often require 50–200 grams per species depending on solubility and test design, and long-term vertebrate studies require substantially more. Samples should be supplied in chemically compatible, tightly sealed containers with stability information, recommended storage conditions, safety data, and clear labeling. Accredited third-party laboratories usually confirm exact quantities during the study plan phase.
Testing Items
The required dataset is assembled from four endpoint families, with the exact scope determined by tonnage band, exposure scenario, and available waivers.
Physicochemical Properties
- Melting point and melting range
- Boiling point and boiling range
- Relative density
- Vapor pressure
- Surface tension
- Water solubility
- n-Octanol/water partition coefficient (log Kow)
- Dissociation constants in water and pH
- UV-Vis absorption spectrum for photoreactivity evaluation
- Flash point, flammability, and self-heating behavior
- Explosive and oxidizing properties (often by theoretical evaluation or screening)
Health Hazard Endpoints
- Acute oral, dermal, and inhalation toxicity
- Skin irritation and corrosion
- Eye irritation and serious eye damage
- Skin sensitization
- Genetic toxicity: bacterial reverse mutation, in vitro chromosomal aberration, in vitro mammalian gene mutation, and, where triggered, in vivo micronucleus testing
- Repeated-dose toxicity (28-day and, at higher tonnages, 90-day studies)
- Reproductive and developmental toxicity screening
- Toxicokinetics for higher-tier assessments
Ecotoxicological Endpoints
- Acute toxicity to fish (96-hour LC50)
- Acute immobilization of daphnids (48-hour EC50)
- Growth inhibition of algae (72-hour ErC50 and NOEC)
- Respiration inhibition of activated sludge
- Long-term toxicity to fish and daphnids for higher tiers, including fish early-life stage and daphnid reproduction studies
- Bioaccumulation in fish where log Kow or screening results indicate potential
Environmental Fate and Degradation
- Ready biodegradability
- Hydrolysis as a function of pH
- Adsorption-desorption in soil and sludge (Koc)
- Direct and indirect photolysis where triggered
Testing Methods
Studies are conducted in accordance with the OECD Guidelines for the Testing of Chemicals and the corresponding Chinese GB/T national standards, for example the GB/T 216xx series covering health-effect tests such as acute oral toxicity (GB/T 21603), skin irritation (GB/T 21604), acute inhalation toxicity (GB/T 21605), acute dermal toxicity (GB/T 21606), skin sensitization (GB/T 21608), and eye irritation (GB/T 21609). Widely referenced OECD test guidelines include:
- OECD TG 102, 103, 104, 105, 109, 112, 115, and 123 for physicochemical properties
- OECD TG 402, 420, 423, and 425 for acute systemic toxicity
- OECD TG 404, 431, 435, and 439 for skin corrosion and irritation
- OECD TG 405, 437, 438, and 492 for eye hazard identification
- OECD TG 406, 429, and the 442 series for skin sensitization, including defined approaches
- OECD TG 471, 473, 476, 474, and 487 for genetic toxicology
- OECD TG 407, 408, 414, 416, 421, and 422 for repeated-dose and reproductive toxicity
- OECD TG 201, 202, 203, 209, 210, and 211 for aquatic toxicity
- OECD TG 111, 106, 121, 301 series, and 305 for environmental fate and bioaccumulation
A scientifically rational test strategy is essential. Tiered testing begins with acute and screening-level endpoints before committing to chronic vertebrate studies, and limit tests at the limit of solubility are applied where appropriate. Exposure concentrations in aquatic studies must be analytically verified, and recommended species include zebrafish (Danio rerio), the water flea (Daphnia magna), and the green alga (Raphidocelis subcapitata). Where animal testing can be avoided, validated in vitro methods, weight-of-evidence assessment, read-across from structurally similar analogues, chemical categories, and documented (Q)SAR predictions are accepted alternatives, provided the scientific justification is transparent and robust.
Applications
Hazard testing data are used directly in registration dossiers submitted to the environmental authority, supporting hazard classification, PBT assessment, environmental exposure modeling, and the risk control measures that accompany a registration certificate. Typical industrial applications include:
- Pre-market registration of new industrial chemicals, specialty monomers, and performance additives destined for the Chinese market
- Site-limited intermediates and strictly controlled process substances under simplified obligations
- Polymer eligibility assessments and supporting data for monomers and residual reactants
- Research, pilot-scale, and product-development quantities proceeding through record-filing
- Due diligence and data-gap filling for substances subject to parallel programs in other jurisdictions, such as REACH-type registration in the European Union, K-REACH in Korea, and premanufacture notification under TSCA in the United States
- Supporting documentation for annual activity reporting, post-registration obligations, and supply-chain compliance declarations
By consolidating all endpoints with a single accredited third-party laboratory or a coordinated multi-laboratory program, companies reduce the risk of inconsistent substance identity, redundant animal use, and dossier deficiencies during technical review.
FAQ
What counts as a new chemical substance in China?
A new chemical substance is any substance not listed on the IECSC, excluding articles, naturally occurring substances in their unprocessed state, and substances already regulated under specific legislation for pharmaceuticals, pesticides, cosmetics, food additives, and similar categories, although intermediates used to synthesize such products generally remain in scope.
How much testing is needed below one tonne per year?
Simple registration typically requires substance identity confirmation, core physicochemical properties, and a limited set of hazard information. Many toxicological and ecotoxicological endpoints can be addressed through (Q)SAR estimates, read-across, or exposure-based waiving with documented justification rather than new laboratory studies.
Are QSAR predictions and read-across accepted instead of testing?
Yes, when the approach is scientifically defensible. Acceptable submissions document the model, its validation status and applicability domain, the reliability of source analogues, and a weight-of-evidence rationale. Authorities may request targeted confirmatory testing where uncertainty remains.
Do the studies have to be GLP-compliant?
Data submitted for registration must be generated under the OECD Principles of Good Laboratory Practice. Reports from laboratories located in OECD MAD adherent jurisdictions are generally accepted, and domestic testing institutions must meet the corresponding national GLP requirements.
How long does a typical testing program take?
Physicochemical endpoints usually require one to three weeks each. Acute aquatic and mammalian screening studies commonly take four to ten weeks, genotoxicity batteries eight to twelve weeks, and long-term studies such as fish early-life stage or reproductive screening three to six months. Complete high-tonnage datasets are typically planned over six to eighteen months.
Are polymers tested differently?
Yes. Polymers are first evaluated against low-concern criteria covering molecular weight, residual monomers, and reactivity. Qualifying polymers often need substantially reduced testing, with attention shifting to the hazard profile of monomers, reactants, and additives above regulatory thresholds.
What deliverables accompany the test results?
A compliant package includes full study reports with GLP compliance statements and quality assurance declarations, raw data and analytical certificates, the certificate of analysis for each test sample, the waiver or read-across documentation, and the integrated hazard and risk assessment report required for submission.
