The on-again, off-again dioxin scare is, well, on-again. An Environmental Protection Agency report says the chemical, in all likelihood, causes cancer and even in trace amounts it may put the immune, reproductive and developmental systems at risk. "We've gone through a period in which the public has pooh-poohed other potential dangers," says TIME senior editor Charles Alexander. "People have said we've over-reacted to alar and radon and asbestos. This report goes against that trend. It says that dioxin really is dangerous."