Scientists at the University of North Carolina, Chapel Hill are trying to help federal regulators improve their chemical screening process. Current tests used to determine whether new drugs and chemicals pose toxicity threats aren't particularly accurate. In fact, initial screening tests are wrong half of the time. A new method for analysis of molecular structure promises to correctly predict a new chemical's toxicity 85 percent of the time. Scientists at UNC say the method could save both regulators and drug and chemical makers time and money. "A lot of chemicals are incorrectly identified as potentially toxic even though in the end they are not toxic and that could have been predicted," Alex Tropsha, a professor at the UNC Eshelman School of Pharmacy, said in a news release. "Companies are forced to run a lot of unnecessary and costly experiments, and because companies run these checks themselves before submitting their products to regulators, there are products that never see the light of day because they are flagged as toxic when they are not." Using the current system, structural alerts sometimes to turn out to be false alarms. Molecules with multiple structural red flags can turn out to be non-toxic when analyzed in their entirety. The new method uses the current test, but couples it with a new computer model designed to predict when isolated structural red flags are likely to be false alarms. "We want to alarm regulators that structural alerts over-predict toxicity while missing truly toxic substances, and offer them much more accurate tools to support regulatory decisions," Tropsha said. The new method is detailed in the journal Green Chemistry.