The motorsport racing industry remains under a "cloud of uncertainty" from strict new regulations that the Obama administration has threatened to impose on race cars for the past year.

The threat of regulation from the Environmental Protection Agency loomed at an annual racing industry gathering in Diamond Bar, Calif., said the industry's trade association, the Specialty Equipment Market Association, which hosted the event at its innovation center.

"This year's event took place as the industry continues to operate under a cloud of uncertainty regarding how it is regulated," the group said Tuesday night. That is still the situation despite assurances from the EPA that it plans to withdraw Clean Air Act regulations on the industry it introduced just over a year ago.

The EPA sought to ban the conversion of vehicles that are modified for the race track, which the association said threatens the future of the sport and the manufacturing industry that supports it. The regulations were tucked away in a rule meant to regulate emissions from big-rig trucks.

The agency said earlier this year that it would withdraw the rule, after the industry and racers staged a major lobbying push to stop the regulations. But the association said Tuesday night from the trade show floor that it isn't confident EPA will fulfill its promise. And even if it does, it still retains the authority to regulate in the future.

"With pressure from Congress, the EPA indicated that it intended to withdraw the specific regulation," the group said. "However, the agency maintains that it has the authority to regulate street vehicles modified exclusively for the track and the businesses that make those products — despite congressional intent."

That has forced the industry to engage in a mid-year push for legislation to exempt the industry from the agency's enforcement authority.

The bipartisan "Recognizing the Protection of Motorsports Act" is pending before Congress. The bill would "make it clear now and in the future that modification of street vehicles for competition is legal and beyond the reach of EPA regulations," the group said.

"The RPM Act addresses any doubts regarding regulation of race cars and gives the public and race car industry much-needed certainty regarding how the Clean Air Act is applied," it said.

The EPA said it plans to withdraw the regulations as soon as it finishes with an interagency review of the truck regulations.

The annual trade show was used to put manufacturers, racers and industry supporters in touch with lawmakers to discuss the rule and push for passage of the legislation.

It is not clear if the bill will move this year, especially with lawmakers taking a lot of time off and focusing on the November elections.