ORRINGTON – As the cleanup of mercury-contaminated soil, river sediment and groundwater at the defunct HoltraChem Manufacturing Co. plant here draws near, a similar operation is taking shape at a sister plant in North Carolina.

Both plants used mercury to make chemicals, mainly for paper companies. Both are on riverbanks – the Orrington plant on the Penobscot River and the Riegelwood, N.C., plant on the Cape Fear River – and both are the subjects of lawsuits. A Brunswick, Ga., plant closed in 1993 and became a Superfund site.

Because HoltraChem, former owner of the remaining plants, folded as a corporate entity in April 2001 and claimed it had no financial resources, the U.S. Environmental Protection Agency is working with former owners to get mercury and other toxins cleaned up. In both cases, former owners have been cooperating with federal and state environmental authorities to address contamination.

AlliedSignal owned the plant in Riegelwood until 1979, when it created HoltraChem. Allied merged with Honeywell International in 1999. Mallinckrodt Inc., which owned the plant in Maine from 1967 to 1982, is the only former owner of that facility which is still in existence.

HoltraChem bought the Orrington plant in 1993. The state Department of Environmental Protection has negotiated with Mallinckrodt, a pharmaceutical company based in St. Louis, to compel it to take responsibility for cleaning up the facility.

Mallinckrodt has done work at the site on a voluntary basis since HoltraChem folded, including hiring an environmental consultant, Camp Dresser & McKee of Cambridge, Mass. Mallinckrodt had been studying the problem for nearly a decade under orders from the EPA. The company has spent millions of dollars on planning and cleanup activities in Orrington.

Despite some similarities between the two cleanups, lawsuits against the plants, both of which are pending, were filed for different reasons.

The Maine People’s Alliance, a statewide citizen advocacy organization, and its powerful national ally, the Natural Resources Defense Council, brought suit against Mallinckrodt in federal court two years ago to compel the company to clean up mercury contamination in the Penobscot River. The trial took place in March in U.S. District Court in Portland. A ruling is pending.

According to the Wilmington Star, a North Carolina daily newspaper, the Riegelwood plant is the focus of a lawsuit filed in January by nine former employees who say they suffered brain damage from mercury exposure. That case, too, has yet to be resolved.

Ernest Waterman, an EPA official based in Boston, said last week that former employees of the Orrington plant have been tested and none appears to have suffered ill health effects as a result of employment by HoltraChem.

Another difference appears to be the amount of work that needs to be done.

In Riegelwood, an estimated 15 tons of mercury must be removed from the plant’s cell building, according to published reports. Mercury also has been found in nearby lagoons, equipment and piping. Authorities have not yet determined if mercury has made its way into local groundwater or into the Cape Fear River.

In contrast, the Orrington cleanup is expected to include dredging the Penobscot River to remove mercury from sediment close to the site. More than 80 tons of mercury left at the site will be moved to a licensed storage facility this summer.

Interim measures are being taken to contain mercury at the site. The EPA is seeking public comment on proposed corrective actions and target levels for a dozen harmful substances at the site, the most dangerous of which is mercury.

Stacy Ladner, the DEP supervisor in charge of the HoltraChem cleanup, said in June that most of the cleanup levels that environmental regulators are shooting for are considered safe to humans and the environment under existing federal and state guidelines for drinking water. Site-specific levels are proposed for toxins not addressed by existing guidelines.

According to a report prepared by the DEP for the Maine Legislature, mercury emissions in Maine have been reduced by nearly 50 percent since 1992, but mercury continues to pose serious health and environmental risks

Emissions from sources within Maine totaled 1,467 pounds last year, down from 2,786 pounds in 1992.

More than half of the 2001 total came from commercial and industrial boilers that burn oil and wood. The second-largest contribution was from so-called “area sources,” including home heating units, wood stoves, burn barrels and use or disposal of consumer products. Much of the mercury that makes its way to Maine originates outside the Northeast.

A naturally occurring element, mercury is a known neurotoxin that impairs the development of fetuses and young children and can result in serious illness and death. According to the DEP report, mercury has been connected to ecological, immune system and cardiological problems. The Legislature in recent years has tackled a series of initiatives to regulate the disposal of mercury.

The DEP study found that 10 percent to 20 percent of women of childbearing age have too much mercury in their blood for a developing fetus. It also suggested mercury is jeopardizing the sustainability of Maine’s loon population.

However, the report also said efforts developed during the past five years to target mercury pollution have produced measurable results.