The Environmental Protection Agency’s approval of more ethanol in the fuel recipe for some cars faces another federal court challenge.

Most car fuel sold around the country is a mixture of 10 percent ethanol and 90 percent gasoline, known as E10, but ethanol supplies, and Congressional mandates for using ethanol, are rising much faster than the market is absorbing the fuel. So in October, acting on the petition of an ethanol industry group, the agency approved a 15 percent blend known as E15, for cars from the 2007 model year and later.

On Monday, however, a who’s who of associations of engine manufacturers filed suit in the United States Court of Appeals for the District of Columbia Circuit. The plaintiffs, which include the Alliance of Automobile Manufacturers, the Association of International Automobile Manufacturers, the National Marine Manufacturers Association and the Outdoor Power Equipment Institute, want the E.P.A.’s decision overturned and sent back to the agency.

“It is clear that the E.P.A. has not fulfilled its statutory obligations to ensure the safe introduction of E15,’’ said Thom Dammrich, head of the marine manufacturers’ group. The agency has stated that younger engines are more tolerant of ethanol, which can damage various parts, but boat engines tend to stay in service much longer than car engines, and a breakdown in the water may be much more of a problem than an engine failure in a car is, opponents of ethanol say. Likewise, the companies that make gasoline-powered garden equipment say that if a seal fails in one of their product, users will suffer the consequences.

The E.P.A. had no immediate comment on the industry groups’ arguments. “We will review and respond appropriately,” an agency spokeswoman said.

Among the arguments raised in the suit is that the E.P.A. does not have the authority to issue a “partial waiver” that covers some cars and not others. (The agency is working backward chronologically in its testing. It had promised a decision on cars from 2001 through 2006 soon afterward, but in November it delayed that decision.)

Opponents say that the higher ethanol blend is not only a problem for cars but also for fuel pumps. On Friday, the American Petroleum Institute, which represents gasoline retailers, warned the E.P.A. that allowing E15 in underground tanks not designed for that mixture would lead to “environmental incidents,’’ or leaks. The institute pointed out that in Energy Department tests, 70 percent of used equipment and 40 percent of new equipment showed “non-compliant or inconclusive results’’ on E15.

The retailers are not enthusiastic about E15 for a variety of reasons. One is that most stations run off a single set of underground tanks, and if these are converted to E15 and only some cars can use that fuel, the stations would have nothing to offer other customers.

How the suit will play into the timing for E15 to enter the marketplace is not clear, because as a new fuel, E15 requires numerous other approvals.