Sir

Thomas Hartung and Costanza Rovinda in their Opinion article (Nature 460, 1080–1081; 2009) argue that the European Chemicals Agency has underestimated the impact of European Union (EU) legislation on animal testing by six times, and that some toxicity tests should be suspended. Unfortunately, pragmatic solutions for the implementation of reduced animal testing under the EU's REACH legislation — for registration, evaluation, authorization and restriction of chemicals — have not yet been formulated in a clear operational manner.

On the basis of the experience in the US High Production Volume Challenge Program, where non-testing approaches have been applied successfully, the goals for REACH can be formulated in a 'smart' manner. In this US programme, around 81% of the chemicals were included in a chemical category and new testing was proposed for fewer than 10% of the human-health and ecotoxicity end-point data needed (K. Van Leeuwen et al. SAR QSAR Environ. Res. 20, 207–220; 2009).

If the United States can waive testing for most of its industrial chemicals, Europe can strive for at least 50% reduction in animal testing over the next five years by applying a similar approach. This will allow us to move away from the slow, traditional, chemical-by-chemical procedures.

Achieving regulatory acceptance for such approaches in Europe is the main challenge. REACH has to assess at least 30,000 chemicals in the next 11 years, an increase of a factor of 300 compared with the past 14 years (G. Schaafsma et al. Reg. Toxicol. Pharmacol. 53, 70–80; 2009). Hence, category approaches are the way forward.