Federal prosecutors are now charging about three times as many people for environmental crimes as they were 10 years ago, and the EPA is sending about four times as many criminal referrals to the Justice Department. And an increasing number of polluters are being punished with jail terms instead of just fines. Last summer, the former head of a Georgia chemical company was sentenced to a record nine-year prison term for exposing workers to dangerous chemicals. A few weeks later, that record was eclipsed when a Florida man received 13 years for dumping toxic waste into Tampa’s sewer system. Still, some people in the environmental community and in U.S. attorney’s offices say the Clinton-Gore administration hasn’t been tough enough on polluting industries, often emphasizing voluntary compliance rather than tough enforcement.