Mercedes is feeling a little bit blue lately, but who can blame them? California, New York, Massachusetts, Vermont, and Maine say that their new generation of BLUETEC diesel aspirated engines don't do enough to reduce harmful pollutants. Effectively, 20 percent of the market will be shut out when these new models debut over the coming months.

Mercedes-Benz has long been an expert builder of diesel engines, producing hundreds of thousands of the alternate-fuel driven power plants every year. Indeed, in Europe alone, a significant portion of the vehicles destined for continental homes are diesel aspirated models. In the U.S., however, Mercedes is having a bit of a problem with its line of diesel engines as more stringent emission control standards makes the marketing of diesel powered cars more difficult. Starting this fall Mercedes will be introducing its all new E320 Bluetec diesel powered car that meets EPA standards; unfortunately, five states will not permit the sale of these models leaving parent DaimlerChrysler feeling a little bit blue.

You have to hand it to Mercedes and to other automakers that are trying to produce fuel efficient cars but are facing increasingly more difficult emissions restrictions in the U.S. It is one thing when the Environmental Protection Agency {EPA} raises pollution standards, but a whole ?nuther thing when individual states seek to raise that standard higher. California, for instance, has long stood on its own requiring automakers to produce cars that met pollution standards that are tougher than the other 49 states? requirements. Recently, New York, Vermont, Maine, and Massachusetts joined in and now require the same tough standards as the Golden State.

In effect the new standards mean that nearly 1 in 5 motorists will not be able to buy a diesel powered Mercedes and not because they cannot afford one but because their state government told them that the cars cannot be sold in their state.

Of course, there isn?t anything wrong with tough emissions controls. However, in light of very high fuel prices are we closing the door on potential fuel savings all in the name for a slight reduction in emissions? As a country of states? rights, the five states can supersede federal emissions requirements. Nevertheless, each state already taxes their citizens greatly and the additional imposition on them doesn?t seem to be quite fair.

Although Mercedes is affected by these requirements they aren?t alone. In fact, Mercedes powered diesel engines are some of the most advanced engines in the world. If Mercedes can?t meet stringent U.S. emissions standards then there is virtually no hope that others will be able to do so either.

As much as the new diesel requirements are tough, they are causing engine manufacturers to study ways to further reduce emissions. Volkswagen, Navistar, Cummins, and others who build diesel engines are continuing with research to find ways to eliminate more pollutants. Perhaps the answer is for leading diesel manufacturers to work together to resolve a problem that could be too expensive to resolve on their own. If they don?t then Mercedes will not be the only automaker crying the blues.