Ground Zero: New studies show Somers contamination larger than expected

A groundwater remedy at the former Burlington Northern tie plant in Somers is “not even close,” Diana Hammer, the Environmental Protection Agency’s project manager for Somers, said last week.

Hammer spoke at a meeting of the Flathead Basin Commission. A soil remedy at the site has already been completed, but sampling completed at the 80-acre site in 2009 and 2010 revealed that the plume of contaminated groundwater at the site extended outside a boundary that was recorded by the EPA in 1989. At that time, the EPA called for treating contaminated soil on-site in a land treatment unit and constructing and operating a groundwater treatment plant. The remedial action started in 1991 with reviews every five years. The EPA collected 145 soil and 196 groundwater samples in September 2011 and February 2012. Hammer said the EPA uncovered more contamination in a shallower aquifer.

The Somers Superfund site was caused by years of milling creosote-covered ties for use in railroad construction in the early 1900s. A plume of creosote-contaminated soil has remained.

Procedures were enacted for treating the contaminated soil and groundwater, but the EPA is in the process of revising the groundwater remedy after they determined that the first one they came up with was not working.

The EPA informed Somers residents of the decision last fall in a community meeting, Hammer said. Most took the news well. “Somers residents just really rolled with it,” she said.

A treatment system was put in place from 1994 to 2007, but later sampling revealed that the contaminated groundwater plume had expanded. The most recent five-year review says the soil remedy protects human health and the environment because the contaminated soil was treated, placed in a land treatment unit at the site, covered with clean-fill soil, and surrounded by a fence. However, Hammer said the EPA and Montana Department of Environmental Quality require more investigation of the contaminated groundwater.

Current technology has exceeded what was available to the EPA when it started working on the Superfund program site in the 1980s, Hammer said. “We didn’t have the tools we have now,” she said. One tool the EPA has started using to investigate groundwater contamination is a laser-imaging tool. The laser is inserted 70 to 80 feet into the ground to find creosote and other chemicals. The newer technology will help the EPA determine the extent of the groundwater contamination. “Right now we don’t understand enough” about the where the contaminated groundwater is located, she said. “We would like an ant farm view. Unfortunately we don’t have that.”

Hammer explained that the contaminated groundwater plume exceeds the standards for benzene and naphthalene. Somers residents use a water supply that is away from the contaminated plume. The bedrock slopes up from the contaminated plume to where the town’s well is, according to Hammer. “We’re not worried about (the well), but we’re monitoring it anyway,” she said. The EPA formerly treated groundwater in contaminated areas and then injected it into the ground with oxygen. That process was used in Libby, Hammer said, but is now considered obsolete. “I was at a conference last year, and it was amazing how many sites like this that haven’t really been cleaned up. And what can we do?” she said.

Somers is one of many polluted sites around the nation. EPA regional director Julie Dalsoglio said cleanup of contaminated groundwater sites across the United States will take “hundreds of years. Milltown may be one of the few exceptions,” she said. That site near Missoula may be able to meet federal standards in five years.

Even though the EPA has completed its fourth five-year review at the Burlington Northern site in Somers, “I can’t draw any conclusions,” Hammer said. This has resulted in a delayed process for the site, which was operated from 1901 until 1986. Hammer said vapor intrusion from the contaminated soil is occurring in four or five homes along Somers Road.  

The EPA and Montana Department of Environmental Quality are working on conservation easements at the site with the Flathead Valley Land Trust, for land owned by Burlington Northern and the Sliters family. Burlington Northern is required to help pay for the groundwater cleanup.