The ToxChip, a DNA microarray chip, allows the monitoring of the expression levels of thousands of different genes at a time, thereby condensing months of painstaking laboratory tasks into a day's work. For toxicology researchers in particular, this tool is important because it promises a more effective way to identify environmental hazards and their effects on DNA. The ToxChip, developed by NIEHS scientists J. Carl Barrett, Cynthia Afshari, and Emile F. Nuwaysir, could transform the way toxicologists approach environmental problems.