Your online News report about assay contamination by chemicals leaching from plastic containers (http://go.nature.com/R7eAFN) doesn't do justice to the scale of the problem and the effort needed to tackle it. The cost of biological experiments performed in standard polypropylene test tubes and polystyrene Petri dishes is enormous, including the price of millions of animals and expensive growth factors. Worse, systematic errors resulting from plastic leaching are biasing conclusions drawn from these experiments. This could have important implications in stem-cell culture, for example, aggravated by the smooth surface of the Petri dish, which is unlike the cells' natural environment.

Companies should address the problem with innovative products. But many reagents extract additives from plastics, and no manufacturer or legislator can address the whole variety of conditions used in laboratories around the world. Rigorously designing appropriate controls could be another way forward.