In 1993, a nearly 50 environment ministers from virtually all Europe, the United States, Canada and Japan adopted a common strategy to help clean up in Central and Eastern Europe. The plan, called the Environmental Action Program, said air pollution was the most serious health hazard in the region, where lead, sulphur and soot had already affected the population. Second, it called for improving and protecting drinking water, which was often laced with heavy metals or toxic chemicals. A third priority, it said, was to stop damaging nature in ways that might be irreversible.