The federal government has used a regulatory loophole to approve nearly two-thirds of the 16,000 pesticides on the market without properly testing them, according to a two-year investigation by the Natural Resources Defense Council, an environmental advocacy group. In a report released on March 27, NRDC criticizes EPA for using a process called conditional registration, which allows pesticide approval before manufacturers have completed rigorous health and safety testing. “EPA has casually approved more than 10,000 pesticides for use in consumer products and in agriculture through this loophole,” says Jennifer Sass, NRDC senior health scientist and coauthor of the report. The agency has done so “without transparency or public comment and, in some cases, without toxicity tests to determine safety guidelines for public use,” she adds. In its report, NRDC calls for major changes in the way pesticides are approved in the U.S. In particular, the group urges EPA to use the conditional registration process sparingly and to ensure that all pesticides already approved under that process comply with the law. NRDC is also calling for EPA to ban any pesticides for which studies are overdue or that pose a public health risk, including nanosilver and the neonicotinoid pesticide clothianidin.