ALEXANDRIA, Va. — Diesel truck engines built after 2007 will be even less efficient to operate than the controversial models now being introduced to meet new federal pollution standards, the Environmental Protection Agency and American Trucking Associations have both said.

WASHINGTON — About 70 members of Congress signed a letter to Environmental Protection Agency Administrator Christine Todd Whitman last week, seeking a one-year delay of EPA’s deadline for selling diesel engines with lower smog-causing emissions.

A federal Ports to Plains Corridor feasibility study — to determine whether to develop a four-lane highway corridor from existing roadways to run between Laredo, Texas, and Denver for increased truck and passenger vehicles to and from the U.S.-Mexico border — is on track for full Senate approval this summer, said a Senate aide.

WASHINGTON - The Senate Health, Education, Labor & Pensions Committee last week approved legislation that would require the federal government to develop mandatory ergonomic regulations to cover a wide range of blue-collar occupations, from truck drivers to package sorters to warehouse employees.

WASHINGTON — Democrats in Congress and environmental groups charged that a Bush administration plan to cut off-road diesel emissions could weaken existing standards for heavy-duty trucks through a complicated government-approved system for trading credits companies earn by reducing pollution.

The U.S. Environmental Protection Agency is having to completely recalculate the numbers of people it alleges are harmed by fine-particulate air-pollution emissions due to a flaw in computer programs it used to produce its estimates.

New federal regulations for transporting hazardous materials have been proposed, drafted and debated since 1994, yet those efforts appear no closer to fruition than they did eight years ago.

California has yet to decide how to punish any diesel engine makers whose new models exceed Oct. 1 federal standards for nitrogen oxide emissions, said a spokesman for California’s Environmental Protection Agency..

Engine maker Cummins Inc. said it is selling few units of its new heavy-duty model, even though it is the only one the federal government has certified that meets new pollution standards that take effect Oct. 1.

Three associations said last week they were interested in joining the America’s Trucking Army campaign, said a spokesman for American Trucking Associations.