As they picked up trash along the Cedar River in Austin one day in June 2017, volunteers noticed something amiss in the river: An oily substance flowing up from the riverbed.
Their observation confirmed what was already suspected: Contaminants from a former gas manufacturing plant on the site persisted in the riverbed and adjoining land off Oakland Avenue East in central Austin. An earlier cleanup of the site, started in 2006, resulted in the removal and treatment of 31,000 tons of soil contaminated with coal tars, sludges, oils, and other chemicals.
The information from the volunteers with the Jay C. Hormel Nature Center’s annual river cleanup highlighted the need for further remediation.
Minnesota Energy Resources Corp. had already reached out to the Minnesota Pollution Control Agency (MPCA) after assuming responsibility for the five-acre site when purchasing the assets of a power company. Minnesota Energy Resources readily enrolled in the agency’s Voluntary Investigation and Cleanup program, which provides technical assistance and oversight. The goal of the program is to return contaminated land — referred to as brownfields — to beneficial uses.
An investigation identified polyaromatic hydrocarbons (PAHs) and petroleum contaminants on the site, which can be harmful to human health and the environment.
Starting in 2018 and finishing this year, crews removed more than 20,000 tons of contaminated soil from the site and 7,000 tons of contaminated sediment from the river and shoreline. Minnesota Energy Resources completed the cleanup, even removing contaminated soil beyond its responsible area. The excavated material went to the SKB Landfill in Austin for disposal.
“This cleanup is a great example of how remediation both restores Minnesota’s natural resources and creates new value for communities. This site, once polluted with potentially harmful substances, has been transformed into beautiful greenspace for the whole community to enjoy,” says MPCA Commissioner Laura Bishop. “The project also demonstrates how partnerships are vital to protecting our environment: We have community members who spoke up, a business that took responsibility by demonstrating sound environmental stewardship, and a watershed district committed to improving the river.”
This site has a long history of pollution. In 1905, a company started manufacturing gas from coal at the site. Interstate Power and Light Company purchased the gas manufacturing site in 1924. By 1928, Jay C. Hormel and residents demanded the company clean up its waste — and foul odors — from the river. Seven years later, after Austin connected to a natural gas pipeline, gas manufacturing at the site stopped.
But its pollutants lurked underground, seeping under the riverbed.
The pollutants persisted even as Interstate Power sold the site in the 1940s and several different businesses operated there for decades. The contamination came to light after Austin suffered a devastating flood in 2004, and the city removed structures from the site as part of flood mitigation. Remediation was also part of repurposing the land. Even though Interstate Power had sold the site decades ago, it remained responsible for the gas plant pollution until selling its assets to Minnesota Energy Resources.
Today, native prairie plants grow there, with water monitoring wellheads among the flowers and tall grasses. The water monitoring wells, in place to detect pollutants in groundwater, will remain to evaluate the cleanup’s effectiveness. If pollutant levels remain low, then the MPCA will recommend removing the monitoring wells, perhaps as soon as 2021.
Meanwhile, the trail is open for bicyclists and the river for paddlers, with several partners on guard against pollution of the past.