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Congressional District # 07


EPA ID# WID006176945
Last Updated: April, 2015

Site Description

Penta Wood Products (PWP), an inactive wood treatment facility, is located 60 miles south of Duluth, Minnesota, and two miles west of the town of Siren, Burnett County, Wisconsin, in the unincorporated town of Daniels in a rural setting on approximately 80 acres of a 120-acre parcel. PWP began operations in 1953 and ceased operations in 1992, due to the inability of the facility to comply with Resource Conversation and Recovery Act (RCRA) drip track regulations. Prior to 1956, wood was treated by dipping poles and timbers into an open tank of pentachlorophenol (PCP) solution or by introducing PCP into the wood under vacuum. In 1956, a pressure-treatment vessel was installed which used a five to seven percent PCP solution in a fuel oil carrier. In 1975, a second pressure process was added which used chemonite, a water-born salt treatment, consisting of arsenate, copper II oxide (ACZA). From over 35 years of operation, PWP had contaminated the site with PCP, and more recently ACZA, by dumping process wastes at various locations on the site, spills, and other poor operating practices. 

In 1986, the Wisconsin Department of Natural Resources (WDNR) investigated operations at PWP where a number of chemical spills had reportedly occurred. In 1987, WDNR requested that PWP assess the environmental conditions at the property. A 1987 investigation found that groundwater at the facility was contaminated with PCP.

Site Responsibility

This site was being addressed through federal action.  The State of Wisconsin took over operations of the groundwater treatment system in 2014.

The State is currently evaluating the remedy in place to determine if there is an alternative remedy that could be implemented to address the remaining contamination on site.  The EPA will continue to work with the State to determine if there is an alternative to addressing the site environmental issues.   

Threats and Contaminants

On-site soils and groundwater were contaminated with PCP, arsenic, copper, and zinc. Ingestion of and direct contact with the contamination prior to remedy implementation could have posed a health threat. Soil contamination also posed a threat to the animals living on and adjacent to the site. 

Cleanup Progress

The United States Environmental Protection Agency (EPA) conducted a $2 million short-term action between April 1994 and June 1996. EPA removed 393 drums of PCP-contaminated oil and sludge; 21,500 gallons of PCP-contaminated liquids; 18,800 gallons of PCP and ammonia copper arsenate (ACA) contaminated liquids; 51 drums of contaminated sludge, 773 tons of contaminated surface soils; and nine drums of asbestos, containing waste. These wastes were properly disposed of at licensed facilities in Indiana and Kentucky. EPA also emptied, removed, and decontaminated about 29 aboveground storage tanks and six underground storage tanks which were filled with PCP and ACA-contaminated sludges. About 4,800 tons of arsenic-contaminated soil were excavated and treated with cement. The treated soils were used to construct a four-acre "BIOPAD" for potential treatment of the PCP-contaminated soils.

The remedial investigation and feasibility study was completed in May 1998.  The record of decision (ROD) was signed on September 29, 1998.  The remedial design (RD) was completed in November 1999.  The remedial action (RA) was completed in September 2000.  The RA consisted of the demolition of buildings, consolidation of PCP and arsenic-contaminated soils in a correction action management unit (CAMU) protective of human health, installation of a  groundwater pump and treatment system, and installation of bio-vent wells and capping the CAMU.  The site is now in the operations and maintenance phase which will last 15-30 years, until cleanup standards are achieved. The treatment plant was upgraded, and became operational in May 2004. The first five-year review was completed March 4, 2005.  The second five-year review was completed January 28, 2010.  A third 5 year review was completed in January 2015. 

Property Reuse

There is no reuse for the property


Remedial Project Manager, U.S. EPA
linda martin (martin.lindab@epa.gov)
(312) 886-3854

Community Involvement Coordinator, U.S. EPA
susan pastor
(312) 353-1325




Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.


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