...the answer varies by manufacturer. Some are planning to offer retrofitting and repowering options to help customers bring their older machines up to date. Others actually discourage it because electronic and other systems don’t synch as well as a new system designed to work together.

But where there’s a will and some skill, upgrades can be done, says Eric Schmidt, equipment superintendent, Sukut Equipment, Santa Ana, Calif. He has repowered 175 pieces of equipment in the company’s fleet. “We’ve even put a 2010-compliant on-road truck engine in a scraper. It meets the air-quality standard, and the machine works fine,” he says.

One reason Sukut repowers so much equipment is to make sure expensive machines, such as a $1.7-million scraper, meet the clean-air standards and can keep working in the nation’s toughest air-quality state, California.

More Smoke Signals

By 2014, on- and off-road diesels alike will run cleaner than ever, but it may not be enough. Based on the well-established pattern of on-road regulation working its way off-road, the EPA’s monitoring of carbon dioxide is only a few years away.

“Greenhouse gases will be the next frontier of regulation,” says Jacob Thomas, Terex vice president. “The amount of CO produced relates directly to how much fuel you burn, so reducing it comes down to getting better fuel economy.” California is now the only state the federal government permits to set its own stricter standards, which include clean-air requirements for older machines that work there. However, as many as 23 other states are waiting to adopt the California code if the federal government grants California the right to enforce it. That prospect could mean fleet owners across the country would have to bring the older equipment in their fleets up to a higher clean-air standard.

In another recent development, jurisdictions across the U.S. are writing in contract-specification requirements for clean construction equipment on projects funded by public money. This proviso could limit contractors from bidding on the work if they don’t have equipment that meets the current clean-air standards. Finally, because of the cost and complexity of the new emission controls, researchers are studying new options for powering clean, off-road equipment (see sidebar, above).

As off-road standards get tougher, it’s apparent that clean air doesn’t come dirt cheap. But construction workers and the public alike will be breathing easier.