EARNS NAVISTAR (The logo is shown on the hood of an International truck on Monday, June 6, 2005, at an International dealership

An effort by diesel truckmakers such as Daimler and Volvo to effectively block Navistar International Corp. from making non-compliant engines and pay a compensatory fine to the US Environmental Protection Agency (EPA) has gone, yes, up in a cloud of exhaust smoke, Bloomberg News reports.

Daimler, Volvo, Detroit Diesel and Mack Trucks all objected to a "pay-for-play" type allowance that let Navistar make diesel truck engines that don't comply with EPA pollution standards and then pay a fine as a result. While the competing truckmakers said they suffered "economic harm" from the allowance, a Washington, DC, appeals court threw the case out. The judge called the claims within the Daimler-led lawsuit against the EPA "speculative," Bloomberg says.

Truck emissions have been a hot-button issue of sorts in recent years. In 2011, the Obama Administration laid out the first-ever fuel-economy mandates for heavy-duty trucks, saying at the time that trucks will be required to increase fleetwide fuel economy by 20 percent by 2018. Those rules, which applied to all trucks over 8,500 pounds, were said to cut emissions by about 250 million metric tons and reduce oil usage by 500 million barrels during the lifetime of the trucks.