Thousands of scientists could be unwittingly ruining their experiments merely by using standard plastic lab equipment, according to a study published in Science. Andrew Holt of the University of Alberta in Edmonton, Canada, found that a disinfectant and a lubricant used in the manufacture of plastic pipette tips, tubes and micro-plates could leach into common solvents, including water (G. R. McDonald et al. Science 322, 917; 2008).

Holt and his team determined that the contaminants are potent enzyme inhibitors, and skewed their drug-activity assays. "People in any big science department will say that they don't trust plastic in some experiments," says Holt. But the compounds responsible had never been identified before, he adds. Eppendorf, a manufacturer of some of the plastic products, says that "so far, we have not experienced any product problems with our customers due to these substances".