The Environmental Protection Agency's (EPA) new report on diesel emissions is an appraisal of past diesel technology, drawing on data collected before the Clean Air Act – primarily during the 1950's, 60's and 70's – rather than an assessment of today's clean diesel technology, according to lobbyist group Diesel Technology Forum. "While the report focused on the past, the future is clean diesel," said executive director Allen Schaeffer. "Diesel trucks and buses built today are more than eight times cleaner than just a dozen years ago." While acknowledging uncertainties about the long-term health effects of exposure to diesel exhausts, the EPA report said studies involving both animal tests and occupational exposure suggest strong evidence of a cancer risk to humans. "Thanks to state-of-the-art engine designs, cleaner-burning fuels and effective emissions-control systems, diesel technology has progressed by quantum leaps over the past 30 years – and will continue to improve its emissions performance in the future," Schaeffer said. Advances in clean diesel technology are constantly lowering emissions of diesel exhaust, as evidenced by EPA's own air quality data showing that from 1990-1998, levels of diesel particulates in the atmosphere dropped by over 37%, Schaeffer said. Schaeffer pointed to the fact that with cleaner fuels, emissions treatment systems and advanced engine technology, diesel trucks and buses will soon be approaching the same environmental performance levels of alternative fuels. He added that a recent test by the California Air Resources Board found that a clean diesel bus running on low sulfur fuel and equipped with the latest emissions-control technology outperformed a natural-gas-powered bus on eight of 11 emissions tests. "Forum members are producing cleaner new engines and fuels, but we're also working to upgrade and modernize existing diesel equipment," said Schaeffer. EPA released its report exactly four weeks before the October 2002 EPA deadline to reduce emissions from diesel engines. Engine makers have been trying to get that date postponed, saying they haven't been given sufficient time to test the new engines and because the added cost of developing those engines will seriously harm the industry. The most-recent attempt to block the deadline came in July, when the White House rejected a plea from House Speaker J. Dennis Hastert (R-IL.) and other lawmakers to postpone the October 2002 EPA deadline to reduce emissions from diesel engines.