The Cincinnati-based utility said a second phase could take the total above $2 billion, depending on how the Bush administration writes new rules governing sulfur dioxide, nitrogen oxide and mercury emissions from power plants.

Cinergy executives touted the projects as the largest environmental construction in the company's history. For perspective, consider: Since 1990 the company has spent about $1.7 billion to reduce sulfur dioxide emissions by about 50 percent and nitrogen oxide emissions by 45 percent.

Even though it is embroiled in environmental litigation, and even though it will eventually have to comply with a new generation of federal regulations, Cinergy deserves credit for its voluntary efforts to reduce emissions. Other utilities are digging in their heels, contributing to the deadlock that has stymied efforts to reach a national consensus on cleaning up older coal-fired power plants.

It's telling, in this regard, that Cinergy is initially investing only in pollution controls certain to be required under any regulatory scenario.

What does or doesn't happen over the next two months could be crucial to determining how much further Cinergy and other utilities go toward meeting their responsibility to clean the air.

The Bush administration is in the final stages of preparing a rule that would tighten limits on power plant emissions. The most recent plan on the table would improve air quality, but it could and should be stronger. If the Bush plan tightened emission limits beyond what's now on the table, particularly on mercury and fine particulates, and moved up compliance deadlines, the administration could credibly claim a significant environmental advance.

Policy makers have a similar opportunity with regard to the other area offering big potential air quality gains: diesel engines. Rules now in place will produce a dramatic improvement in emissions from new diesel engines. But because diesels last so long -- it's not uncommon to get 20 to 30 years use out of a properly maintained engine -- it will take several decades to achieve a pronounced improvement in air quality. Manufacturers, however, have come up with effective and fairly inexpensive retrofit kits for most existing engines. If policymakers were to mandate their use, or offer incentives to companies and individuals that install them, there would be immediate gains in air quality.

Both sets of actions -- improved controls on power plants and diesel engines -- would go a long way toward helping such regions as Greater Cincinnati comply with the new generation of federal air quality regulations.

Under the new rules, Boone, Kenton and Campbell counties in Northern Kentucky and Hamilton, Butler, Warren, Clermont and Montgomery counties in Southern Ohio are in violation of federal ozone standards. Many of them are expected to wind up on the non- attainment list for fine particulates when it is published later this year. Ohio, Kentucky and Indiana are among the states now trying to write plans for bringing their communities into compliance.

Northern Kentucky got a taste of how stringent those rules could be the other day, when the EPA rejected a state proposal to claim as a credit the 2001 shutdown of an arc furnace at the Newport Steel factory.

According to the Ohio Environmental Council, improved controls on power plants and engines probably won't be enough by themselves to bring Greater Cincinnati into compliance -- but would put us close. Heck, between that and cleaner fuels and a few other steps, maybe Kentucky and Ohio could get away with eliminating their E- Check programs.

The E-Check programs ought to go, because pollution controls built into cars these days are fast making them redundant. We're all paying for those controls, of course, in the price of the car, just as we'll pay for the environmental program Cinergy is launching in the form of higher rates. But these are costs we can afford, and the paybacks -- in terms of our health, quality of life and economic development potential -- are enormous.