ORRINGTON – Contaminated buildings and tanks used to create chlorine, pesticides and papermaking chemicals at the now defunct HoltraChem Manufacturing Co. are on their way out of town.

Phase five of the dismantling and remediation plan for the 235-acre former chemical plant site on the banks of the Penobscot River has been approved and will include removal of seven buildings and 20 tanks.

“We are moving deliberately and prudently to protect the Penobscot River and the health of the people of Maine,” state environmental Commissioner David Littell said Wednesday in a press release. “We have made significant progress at the HoltraChem site, removing highly contaminated buildings, tanks and other material, and, as [Gov. John Baldacci] said, we should be proud of that effort.”

During a press conference at the Blaine House in Augusta, Baldacci described the project as “the environmental contamination site with the highest priority” for his administration, according to information from Baldacci’s press office. The state’s Department of Environmental Protection took over management of the cleanup project from the federal government in 2003.

The nitromethane building, the old well pump station, three river well pump houses, the filtered brine pump house and the paint shop will be removed as part of phase five, scheduled to take 61/2 months to complete.

The cell building, which at one time housed the mercury cells used in the chemical processing, was removed as part of phase two of the remediation project, conducted by Camp, Dresser & McKee, an environmental firm hired to do the cleanup. CDM is using the old HoltraChem administrative building as an office, but is based in Cambridge, Mass.

All that remains of the chemical processing building is a sealed concrete slab with trenches, Stacy Ladner, project supervisor for the DEP, informed the in town in her August HoltraChem report.

“The site is starting to appear very different as the work has focused on the dismantling of structures in preparation for long-term remedial activities,” Baldacci said.

The multimillion-dollar cleanup project was started by CDM in March 2003 with removal of aboveground liquid mercury and the cleaning of the mercury cells.

In addition to removing the contaminated cell building, the second phase also included removing outdoor piping.

Phases three and four, which overlap each other and include cleaning of residual material in tanks, draining of rectifiers and transformers, and removal of a dozen buildings contaminated to the point that the demolition debris was considered hazardous waste for mercury, are nearly completed. The fifth phase is scheduled to begin this month or early next month.

Owned by various companies over the years, HoltraChem produced chemicals and pesticides from the mid-1960s to 2000, when it closed in bankruptcy.

Mallinckrodt Inc. owned and operated the plant from 1967 to 1982 and is the sole former owner still in existence. The company is in the middle of a multiphase cleanup project that already has removed tons of mercury and other contaminants from the former chemical plant site.

Baldacci thanked the Maine People’s Alliance, a grass-roots organization that works on environmental, health and other social issues, as well as Maine and Orrington residents for their partnering with the DEP to clean up the site.

“We remain committed to being aggressive about minimizing the risks to the environment and public health posed by the long-standing and toxic contamination on this property,” he said.