Gov. Baldacci is right that the best way to fully clean up the former HoltraChem plant is to dig up and remove tons of soil contaminated with mercury. Unfortunately, the company now liable for cleaning up the Orrington plant objects to this costly plan and favors containing the contaminated soil on site. Simply burying the problem will not make it go away and will hinder the long-awaited redevelopment of the riverfront property while leaving lingering doubts in the minds of local residents about the safety of groundwater in the area.

The Maine Department of Environmental Protection looked at four options for containing the mercury pollution from waste in five landfills at the plant. The least costly options involved putting all of the contaminated soil in unlined landfills on the property. This leaves the risk of contaminants seeping into the ground and, ultimately, the river.

A third option was to construct a new lined landfill where all the waste would be placed. The last option, and the one favored by the DEP commissioner, was to excavate all the waste and truck it to a landfill that handles hazardous waste. This is estimated to cost $200 million.

As the governor said: “If you’re going to move it around, you might as well move it off the property and deal with it once and for all. That really makes the most sense.”

Science supports this approach. The Environmental Protection Agency, under both the Clinton and Bush administrations, has ruled that dredging and removing – not simply covering up – soil contaminated with PCB is the best way to clean up the Hudson River in New York. Both mercury and PCBs are highly toxic and are concentrated as they move up the food chain.

General Electric for decades dumped PCBs into the river and is responsible for the cleanup, according to the EPA. The company has fought the Hudson clean-up – estimated to cost $400 million – every step of the way.

In Maine, Mallinckrodt Group Inc., a St. Louis-based pharmaceutical company, is obligated, through a DEP order, to clean up the HoltraChem site. It wants to consolidate the contaminated soil on site and cap it. Like the DEP’s two least-costly options, this is not a solution. Mallinckrodt is the only former owner of the site that is still in business. So far, it has cooperated with DEP and EPA efforts to clean up the 235-acre property. It can, however, appeal this DEP ruling that the contaminated soil be removed. This would be unfortunate because it would further slow down work at the site, which the town of Orrington is eager to redevelop.

The first priority is to clean up the site so that it no longer poses a threat to the health of nearby residents or to the environment. Once that is done, Mallinckrodt can look for other former owners to share the cost.

Without removing the mercury, the environmental damage is likely to get worse, which will only cost Mallinckrodt more to clean up later.