Toxicology testing for new chemical substance registration is the core health-hazard data requirement that determines whether a substance not listed on the existing chemical inventory can be manufactured in or imported into the Chinese market. This technical guide summarizes the regulatory framework, the required mammalian toxicity endpoints, internationally recognized OECD and GB test methods, sample preparation requirements, and practical compliance considerations for registration teams and accredited third-party laboratories.
Technical Overview
In China, new chemical substances—those not listed on the national inventory of existing chemical substances—must undergo environmental management registration before manufacture or import. The governing regulation is the Measures for the Environmental Management Registration of New Chemical Substances (Ministry of Ecology and Environment Order No. 12), effective from January 1, 2021, which replaced the previous Order No. 7 of 2010. Health-effect toxicology data form a central part of the registration dossier and directly drive hazard classification, risk assessment, and the registration conditions imposed by the authority.
Order No. 12 establishes a tiered registration system in which the required data package scales with the annual tonnage and the hazard profile of the substance:
- Record filing: applies to low-volume uses (generally below 1 tonne per year) and specific categories such as qualifying polymers of low concern; routine toxicology testing is not required, although the authority may request supplementary information.
- Simplified registration: applies to annual volumes of 1 tonne or more but below 10 tonnes; requires a base set of health-effect data covering acute toxicity, irritation, sensitization, and mutagenicity.
- General registration: applies to annual volumes of 10 tonnes or more; requires the base set plus repeated-dose toxicity, reproductive and developmental screening, and additional genotoxicity or toxicokinetic data as triggered by tonnage and study findings.
All mammalian toxicology studies supporting a registration must be conducted under Good Laboratory Practice (GLP) principles. Health-effect studies may be performed at overseas laboratories operating in compliance with OECD GLP, whereas ecotoxicological studies must be carried out by domestic test facilities qualified under the national GLP recognition system for new chemical substance environmental management. Data waiving through quantitative structure-activity relationship (QSAR) modelling, read-across from structurally similar analogues, weight-of-evidence analysis, or scientifically validated in vitro methods may be proposed, subject to case-by-case review by the registration authority.
Testing Samples
Test Substance Characterization
The test sample must be representative of the substance intended for commercial manufacture or import. The submitter should provide a complete characterization package, including substance identity, purity, composition of main constituents and impurities, water solubility, partition coefficient, vapour pressure where relevant, and stability information. For pure organic substances, a purity of 98% or higher is generally recommended for toxicology testing; technical-grade materials are acceptable when they represent the actual commercial grade, provided the impurity profile is fully documented.
Sample Quantity Guidelines
The required sample volume depends heavily on the selected endpoints and study design. Typical quantities are as follows:
- Bacterial reverse mutation assay: approximately 5–20 g of test substance.
- In vitro chromosomal aberration or micronucleus assays: approximately 5–20 g.
- Acute toxicity studies (single route): approximately 20–100 g.
- Skin and eye irritation and sensitization studies: approximately 10–50 g.
- 28-day repeated-dose toxicity: approximately 100–500 g.
- 90-day subchronic toxicity: approximately 1–5 kg.
- Reproductive and developmental screening studies: approximately 200 g to 1 kg or more.
Handling, Labeling, and Documentation
Samples should be supplied in stable, tightly sealed containers labeled with substance name, batch or lot number, purity, net weight, production date, and recommended storage conditions. A safety data sheet (SDS) and, where available, analytical certificates must accompany the sample. A retained reference sample should be kept by the sponsor, and a documented chain of custody should be maintained from shipment to study completion to ensure data traceability during authority review.
Testing Items
The health-effect test package is structured around internationally recognized hazard endpoints. The composition of the package depends on the registration tier and exposure scenarios.
Core Endpoints for Simplified Registration
- Acute oral toxicity, and where relevant dermal or inhalation toxicity, reflecting the anticipated exposure route.
- Skin irritation or corrosion.
- Eye irritation or serious eye damage.
- Skin sensitization.
- Mutagenicity, principally the bacterial reverse mutation assay, supplemented by in vitro cytogenetic testing where exposure or structural alerts warrant.
Additional Endpoints for General Registration
- Repeated-dose toxicity, typically a 28-day oral study including recovery groups; a 90-day subchronic study may be triggered by tonnage or findings.
- Reproductive and developmental toxicity screening, or prenatal developmental toxicity where indicated.
- Additional genotoxicity confirmation in vivo when in vitro results are positive.
- Toxicokinetic (adsorption, distribution, metabolism, and excretion) information to support dose extrapolation and risk characterization.
- Supplementary studies such as neurotoxicity, immunotoxicity, or carcinogenicity testing, required only in exceptional cases based on hazard signals.
The resulting data feed directly into hazard classification under the GB 30000 series of national standards, which implement the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) in China, and support SDS authorizing and risk management recommendations in the registration dossier.
Testing Methods
Test methods must comply with the OECD Guidelines for the Testing of Chemicals or the equivalent Chinese GB/T standards in the chemical hazard testing series (for example, GB/T 21603 for acute oral toxicity), both of which are accepted by the registration authority. The commonly applied guidelines are:
- Acute oral toxicity: OECD TG 420 (fixed-dose procedure), TG 423 (acute toxic class method), or TG 425 (up-and-down procedure).
- Acute dermal toxicity: OECD TG 402.
- Acute inhalation toxicity: OECD TG 403 or TG 436.
- Skin irritation or corrosion: OECD TG 404 in vivo, or in vitro alternatives under TG 430, TG 431, TG 435, or TG 439 using reconstructed human epidermis models.
- Eye irritation or corrosion: OECD TG 405 in vivo, or in vitro alternatives under TG 437 (bovine corneal opacity and permeability), TG 438 (isolated chicken eye), TG 491, or TG 492 using reconstructed human cornea-like epithelium models.
- Skin sensitization: OECD TG 406 (guinea pig maximization or Buehler), TG 429 (local lymph node assay), or in vitro and in chemico methods under TG 442A, TG 442B, and TG 442C, with defined approaches described in TG 497.
- Genetic toxicity: OECD TG 471 (bacterial reverse mutation), TG 473 (in vitro mammalian chromosomal aberration), TG 487 (in vitro mammalian cell micronucleus), and TG 474 (in vivo mammalian erythrocyte micronucleus).
- Repeated-dose toxicity: OECD TG 407 (28-day oral), TG 408 (90-day oral), with dermal and inhalation variants under TG 410, TG 411, TG 412, and TG 413.
- Reproductive and developmental toxicity: OECD TG 421 and TG 422 (screening), TG 414 (prenatal developmental), TG 443 (extended one-generation), and TG 415 or TG 416 for full multigeneration studies.
- Toxicokinetics: OECD TG 417.
Each study report must include full test substance characterization, dose justification, GLP compliance statements, deviations from the guideline, and raw data sufficient for independent reconstruction of the conclusions. Test reports submitted with a registration application are generally expected to have been issued within five years prior to submission, unless scientific justification for older data is provided. Positive results in tiered testing frequently cascade into confirmatory higher-tier studies, so early endpoint planning and integrated testing strategies materially reduce both cost and timeline.
Applications
Toxicology testing for new chemical substance registration supports a wide range of industrial and regulatory scenarios:
- Market entry for novel substances intended for manufacture in or import into China that are absent from the existing chemical inventory.
- Specialty and fine chemicals, polymer additives, electronic and battery chemicals, catalysts, and process aids introduced at research, pilot, or commercial scale.
- Intermediate and site-limited substances requiring record filing or simplified registration under volume-based thresholds.
- GHS-aligned hazard classification and SDS authoring for downstream communication along the supply chain.
- Parallel or leveraged compliance programs, since OECD-based mammalian toxicity datasets prepared for this framework can often support registrations under other chemical control regimes worldwide.
- Product stewardship, occupational exposure assessment, and risk management measure design for newly commercialized substances.
FAQ
What toxicology data are required for simplified registration?
Simplified registration generally requires acute toxicity data for the relevant exposure route, skin irritation, eye irritation, skin sensitization, and a bacterial reverse mutation assay. In vitro cytogenetic testing may be added based on exposure patterns or structural alerts. The exact package is confirmed during the pre-submission consultation process with the registration authority.
Can overseas GLP study reports be used?
Yes. Health-effect toxicology studies performed at overseas laboratories operating under OECD GLP principles are acceptable for registration. Ecotoxicological studies, by contrast, must be performed by domestic test facilities qualified under the national GLP recognition system for new chemical substance environmental management.
Are QSAR, read-across, and in vitro methods accepted instead of animal testing?
They can be. Scientifically justified QSAR predictions, read-across from close structural analogues with adequate data, weight-of-evidence arguments, and validated in vitro methods (particularly for irritation and sensitization endpoints) may be proposed as data waivers or replacements. Each justification is reviewed case by case, so robust documentation of analogue similarity and prediction reliability is essential.
What sample purity is acceptable, and how should samples be prepared?
A purity of 98% or higher is recommended for test purposes, but the decisive criterion is representativeness of the commercial substance. Technical-grade samples are acceptable when the full composition and impurity profile are documented. Samples must be properly labeled, accompanied by an SDS and analytical certificates, and shipped under conditions that preserve stability.
How long do the studies take?
Typical durations, excluding scheduling and test-substance characterization, are two to four weeks for acute toxicity, four to eight weeks for genotoxicity assays, three to four months for a 28-day repeated-dose study, six to nine months for a 90-day study, and five to eight months for reproductive and developmental screening. Planning the integrated package in advance prevents sequential delays.
How recent must the test reports be?
Reports used in the registration dossier are generally expected to have been issued within five years before the application date. Older reports may be accepted when supported by a scientific rationale demonstrating the continued validity of the data for the substance as registered.
