GLEN ALLEN -- Jan 28 - Knight Ridder/Tribune Business News - Scott Harper The Virginian-Pilot, Norfolk, Va.

Virginia will pursue one of two strategies for cutting mercury emissions from power plants, the State Air Pollution Control Board decided Friday.

Regardless of which plan is chosen by the end of the year, both options would be tougher than the one recommended by the Bush administration, which would allow Virginia utilities to buy and sell "mercury credits" on the open market with any other state .

Environmentalists and public health advocates decry the Bush plan as too forgiving to utilities, and they are challenging the proposed federal rules in court.

Meanwhile, states are facing a decision in trying to curb mercury, a highly toxic air pollutant: adopt the Bush plan or do something else. Virginia, like its neighbors North Carolina and Maryland, appears headed for the latter.

A strategy favored by the Virginia Department of Environmental Quality, and one of the two options endorsed by the state air board Friday, would cap the total amount of mercury released from coal-fired power plants each year at 435 pounds by 2015 . That total amount of emissions was 1,239 pounds in 2003 .

Utilities such as Dominion Virginia Power, which operates the most coal-fired plants in the state, with eight, could trade mercury credits within its own network, but could not sell or buy them outside of Virginia, according to the DEQ strategy.

Such credits would be created when a utility equips one of its plants with anti-pollution technology that goes beyond what is required under its state permit. This leaves a cushion, a credit, that could then be sold or socked away and used to offset higher-than-permitted pollution at a different plant.

The other option forwarded by the air board Friday would require that each smokestack at every coal-fired power plant meet specific emission limits for mercury -- an 80 percent reduction by 2010 , and 90 percent by 2013 .

No trading of credits would be allowed under this alternative, devised by a coalition of air-quality directors in states and counties across the country.

Collectively, utilities could face upgrades costing more than $900 million to meet the 90 percent rule. To achieve a 70 percent reduction under the DEQ strategy, state officials estimate that improvements could cost $640 million.

Executives from Dominion and other utilities have said they favor trading of mercury credits. As such, utilities are expected to press for the DEQ strategy -- or go one step further and attempt to pass legislation in the Virginia General Assembly, which would mandate that the state follow the free-trading Bush plan.

Such a bill, SB651, has been introduced by state Sen. Phillip P. Puckett , a Democrat from coal country in southwest Virginia. Its fate is pending.

The air board voted unanimously Friday to send the two regulatory options out for public comment for 60 days after they are published in the state register. After that, the board will weigh the comments, meet again and pass one of the two plans.

Or adopt some type of hybrid.

"I would hope the tension created by these two proposals would result in something creative, something with a little bit of both," said Hullihen W. Moore , one of four members of the air board.

One other strategy targeting non-utility industries that generate significant mercury emissions also was adopted Friday and will be sent out for public comment.

Reach Scott Harper at (757) 446-2340 or scott.harper@pilotonline.com .