NORTH HAVEN, Conn. -- School transportation officials expressed skepticism about a February report that claims diesel school bus exhaust exposes children to significant health risks.

Released by the environmental advocacy organization Environment and Human Health, Inc., the study said "children are exposed to diesel exhaust from school buses at levels far above those predicted by current government monitoring efforts."

Mike Martin, executive director of the National Association of Pupil Transportation, questioned the report and its findings, referring to an early study with similar results that has since been contradicted by a peer review and another study that came to opposite conclusions.

"I think its safe to say that from my perspective their results are viewed with suspicion, that's for sure," Martin said. "It's conceivable that they came to conclusions and then looked for the facts to prove them."

The study placed "ultra-sensitive" monitors on children and recorded air quality readings throughout the day. "For short periods, the research showed exhaust levels 5 to 10 times higher than government standards," said the study's lead author Dr. John Wargo, Yale professor of risk analysis and environmental policy.

These "short periods," however, were just 10-second intervals when students entered and exited buses.

The study monitored levels of coarse particles, which are caused by dust, and fine particles, which are produced by fossil fuel combustion. But in one chart that measured fine particle exposure of five children, the two children with the highest rates of exposure did not ride buses; they walked to school.

According to Charles Gauthier, Executive Director of the National Association of State Directors of Pupil Transportation Services, school transportation industry officials are eager to conduct a peer review of the EHH study, questioning the organization's political agenda. "Let's wait and make sure we understand everything before we make decisions that affect health of our children," Gauthier said.

The study also drew a link between childhood asthma and diesel exhaust.

"One of the things I find ironic is that during the Olympics there was a report that one in five U.S. athletes suffered from some form of asthma," Martin said. "These are world-class, Olympic-caliber athletes and one in five has asthma. I don't know how many of them rode school buses, but to hold school buses responsible for the increase in asthma is a bit of a stretch."

Released on "Good Morning America," the study was portrayed as a Yale University product, though the EHH commissioned and financed the study. The University of Connecticut's Environmental Research Institute conducted the study's air quality monitoring.

The report offered several recommendations, including retrofitting buses by 2003 with particle traps and catalytic converters to reduce emission, requiring use of ultra-low sulfur fuels and prohibiting bus idling.

Martin said the industry probably would support voluntary anti-idling restrictions, pointing to a number of states that already use such policies. But he questioned why the pupil transportation industry should be held to higher standards than other diesel-dependant industries.