Vapor Intrusion Becomes Next Legacy of St. Louis Park Creosoting Company

The EPA's Vapor Intrusion Sample

The U. S. Environmental Protection Agency begins vapor intrusion testing in St. Louis Park, Minnesota, sometime in March or April. This involves air sampling in 30 homes and apartments and is from a long legacy left behind by Reilly Tar & Chemical Corp. The company, and its predecessor the Republic Creosoting Company (later purchased by Reilly), made coal tar and preserved wood in the nearby area on 80 acres from 1917 to 1972.

The EPA & Vapor Intrusion

The EPA is looking for concentrations of polycyclic aromatic hydrocarbons (PAH) that may be moving through vapors into living spaces from water and soil below them. The process of vapor intrusion is a fairly new focus on the environmental front. The EPA writes that “vapor intrusion occurs when chemicals in the underground water give off potentially hazardous gases that can rise up through the soil and seep into buildings through foundation cracks and holes.”

The Reilly Tar site, as it is known today on the EPA’s Superfund National Priority List, has been in the news since 1918 when a citizen protested to the village council about the obnoxious odors coming from the plant. Later, when the city’s first water well was contaminated with creosote, forcing its closure, the site’s notoriety was firmly established. Of course it didn’t help that at one time the company simply discharged “wastewater containing creosote and cola tar from plant operations ...into... a ditch that drained to a swamp south of the site.”

By one account 6,000 gallons per week were sent floating down a series of ditches and into the local swamp. The company also used abandoned water wells to get rid of creosote and oil. From 1941 until the facility ceased operations, treated effluent sent to the swamp still contained between 100 and 1,000 micrograms per liter of phenols, oil and grease.

According to Chemical and Engineering News (CEN), the vapor intrusion landscape is filling quickly with lawsuits that are shaping up to be significant challenges for the chemical and manufacturing industries, and old chemical plants are a major concern. DuPont is seeing the issue come back around for a third time with a former munitions plant in Pompton Lakes, New Jersey. To date the company has installed basement ventilation systems in 217 homes and is checking into drilling additional wells that can be used to treat contaminated ground water. CEN quotes “Martha L. Judy, a professor at Vermont Law School, who calls old chemical plant sites ‘the problem that keeps on giving."

Vapor Intrusion Is New To Science

Because vapor intrusion is a newly recognized issue, the science hasn’t caught up with it yet making remediation a sort of high stakes guessing game. Spokespeople for chemical companies even admit it is “new science” with people just now learning how to deal with it.

In St. Louis Park much of the remediation efforts have focused on cleaning up contaminants at the source - in the groundwater. Reilly agreed in 1986 to clean up its old site and maintain the city’s drinking water for 30 years. Two activated carbon treatment plants treat the water from some of the city’s wells and more than 30 wells pull water from contaminated aquifers for treatment and disposal. One account estimates 6.2 billion gallons of water have been treated. Still, the contamination lingers, and now potentially continues through vapor intrusion.

Here’s an EPA fact sheet about vapor intrusion related to this Superfund site.