The OECD Test Guidelines are recognised internationally as the standards for non-clinical environment and health safety testing of chemicals and chemical products. They are an integral part of the Council Decision on the Mutual Acceptance of Data and are used to support chemical safety regulations in many countries. Each Test Guideline provides sufficient detail for chemicals to be tested in the same manner in laboratories around the world.

These Guidelines are continuously expanded and updated to ensure they reflect the state-of-the-art science and techniques to meet member countries regulatory needs. The Guidelines are elaborated with the assistance of experts from regulatory agencies, academia, industry, environmental and animal welfare organisations. 

The OECD Guidelines for the Testing of Chemicals are split into five sections:

• Section 1: Physical Chemical Properties
• Section 2: Effects on Biotic Systems 
• Section 3: Environmental Fate and Behaviour 
• Section 4: Health Effects  
• Section 5: Other Test Guidelines

Several Test Guidelines have been published on 25 June 2024. These guidelines ensure testing keeps pace with scientific progress, and that they promote chemical testing best practices, in line with the Replacement, Reduction and Refinement of animal experimentation (3Rs) Principles.

Three new Test Guidelines:

• Test No. 252: Rapid Estrogen Activity In Vitro (REACTIV) assay
• Test No. 253: Short-term juvenile hormone (JH) activity screening assay in Daphnia magna
• Test No. 321: Hyallela Azteca Bioconcentration Test (HYBIT)

The following Test Guidelines were updated:

• Test No. 442D: In Vitro Skin Sensitisation
• Test No. 467: Defined Approaches for Serious Eye Damage and Eye Irritation
• Test No. 496: In vitro Macromolecular Test Method for Identifying Chemicals Inducing Serious Eye Damage and Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage

The following Test Guidelines were corrected/clarified:

• Test No. 493: Performance-Based Test Guideline for Human Recombinant Estrogen Receptor (hrER) In Vitro Assays to Detect Chemicals with ER Binding Affinity
• Test No. 492: Reconstructed human Cornea-like Epithelium (RhCE) test method for identifying chemicals not requiring classification and labelling for eye irritation or serious eye damage
• Test No. 442C: In Chemico Skin Sensitisation
• Test No. 442B: Skin Sensitization
• Test No. 403: Acute Inhalation Toxicity
• Test No. 492B: Reconstructed Human Cornea-like Epithelium (RHCE) Test Method for Eye Hazard Identification
• Test No. 442E: In Vitro Skin Sensitisation

This Series includes publications related to testing and assessment of chemicals; some of them support the development of OECD Test Guidelines (e.g. validation reports, guidance documents, detailed review papers).