For the first time in the history of a recent Society of Automotive Engineers survey, environmental issues led the list of industry challenges, topping the perennial No. 1 — cost-cutting.

No wonder: Congress passed legislation in January 2008 mandating a 40 percent increase in the Corporate Average Fuel Economy of passenger cars and light trucks, phased in from 2010 to 2020, to 35 mpg. Considering it can take five years to develop an all-new vehicle, 2010 is already here, and 2020 isn’t far off.

SAE members, including designers and engineers for automakers and their suppliers, are the people in the trenches who are going to have actually come up with ways to meet the new standards. And the fact that implementation of the new rules could change between now and then only adds to their anxiety.

The practical interpretation of the fine print within the rules (read: search for loopholes) has only just begun. In addition, there will almost certainly be a raft of lawsuits filed in connection with the new standards, which could also have an impact.

“While cost reduction remains very important, the automotive industry’s emphasis is on the environment and the demands that puts on innovation,” said Chris Murphy, head of DuPont Automotive Americas, the giant auto industry supplier that co-sponsored the survey with the SAE.

It’s fair to point out that DuPont, which coined the term “Better Living Through Chemistry,” has a transparently self-serving agenda of calling attention to its high-tech automotive materials that save weight, among other virtues that are critical to achieving higher gas mileage. Leaving nothing to chance, DuPont helpfully names a few of those materials, in an April 10 press release describing the results of the 14th annual SAE survey.

However, there’s no doubt the survey accurately reflects the biggest bogeyman in the SAE’s “closet of anxieties,” to cite the comic strip, “Bloom County.”