An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Hazardous Waste Cleanup: Nova Chemicals in Monaca, Pennsylvania

On this page:

Cleanup Status

The final remedy for the facility is complete and consists of a Technical Impracticability (TI) Zone for contaminated groundwater beneath portions of the Central Plant/Styrene II and Over-The-Hill Areas, monitored natural attenuation outside the TI Zone, the establishment of a groundwater monitoring program for the Central Plant/Styrene II Area and the former waste disposal areas, and the implementation of engineering and institutional controls summarized below and described in more detail in the Statements of Basis for the active and inactive portions of the facility. The Final Decision to implement the final remedy for the inactive portion became effective on September 28, 2018, and the Final Decision to implement the final remedy for the active portion became effective on January 29, 2019.

Cleanup Background

Several investigations of the facility have been conducted with PADEP oversight.  Remedial investigations and risk assessments for each of the areas were completed in the 1990s and led to final reports and releases of liability under the Act 2 program for each of the six areas between 1999 and 2001.  Air sparging and soil vapor extraction remedial systems operated for two years in the Central Plant and Over-The-Hill Areas.  Raccoon Creek and East and West Landfill Areas were capped with a soil and vegetation cover, and mercury-contaminated soil from the Phthalic Anhydride Plant Area was excavated and disposed of off-site.

An environmental covenant was recorded for the inactive portion of the facility in 2014 that codified several restrictions detailed further below under “Institutional and Engineering Controls”.

Results from groundwater sampling in the East Landfill Area in 2014, the Central Plant/Styrene II Area in 2016, the Over-The-Hill Area from 2010 to 2016, and the Raccoon Creek Area from 2015 to 2016 suggest that contaminant levels in groundwater are stable or decreasing. Results from River Wells along the Ohio River bank and surface water and sediment sampling of Raccoon Creek in 2016 suggest that surface water is not impacted above protective levels, although some impact to Raccoon Creek sediments from heavy metals was noted.

Top of Page

Site Description

Interactive Map of Nova Chemicals in Monaca, Pennsylvania

View larger map

The former ARCO Chemical facility is located on an approximately 420-acre plot of land on the south bank of the Ohio River in Potter Township, Beaver County, Pennsylvania.  The facility was initially constructed in 1942 by Koppers United Company on behalf of the US government.  Processes at the facility at this time focused on manufacturing organic chemicals used to make synthetic rubber.  In the 1940s-50s, Koppers used the facility for the manufacture of polystyrene and Dylite (expandable polystyrene).  Although the manufacturing of polystyrene and expandable polystyrene has been ongoing since that time, the facility has had many owners: Sinclair-Koppers in the 1960s, ARCO from the 1970s to the 1990s, and NOVA Chemicals from 1996 to the present.  ARCO retained ownership of the four inactive areas of the facility (described below) until 1998 when ARCO was sold to Lyondell Chemical Company, who then became owner of the inactive areas.  The inactive areas of the facility were owned by the Lyondell Environmental Custodial Trust as a result of Lyondell’s 2009 bankruptcy until December 2017, when the Beaver County Corporation for Economic Development purchased the East Landfill Area and Phthalic Anhydride Area. The Lyondell Trust continues to own the West Landfill/Dravo Quarry Area and the Raccoon Creek Area.

For remedial purposes, the facility was broken into six different areas: the Central Plant/Styrene II Area (71 acres) and the surface impoundments and wastewater treatment plant in the Over-The-Hill Area (12 acres) are the two areas still operational; the Raccoon Creek Area (18 acres), West Landfill/Dravo Quarry Area (14 acres), East Landfill Area (54 acres), and Phthalic Anhydride Plant Area (4 acres) are all inactive areas.

Top of Page

Contaminants at this Facility

Primary contaminants include benzene, toluene, ethylbenzene, xylenes, and styrene (BTEXS).  Soil and groundwater are the primary media impacted by the contaminants.  Potentially complete exposure pathways to this contamination include vapor intrusion from groundwater and soil contamination into the indoor air of occupied on-site buildings, direct contact of contaminated soil or groundwater during intrusive operations, and direct contact and/or ingestion of contaminated sediment or surface water. However, none of these exposures are likely to be significant; see human exposures environmental indicator under “Reports, Documents, and Photographs” for more information.

Top of Page

Institutional and Engineering Controls at this Facility

The 2014 environmental covenant covering the inactive portion of the facility restricts land to non-residential purposes; prohibits use or consumption of groundwater or Raccoon Creek surface water (within Facility boundary); requires O&M of engineered structures including fences, capped areas, and stormwater management devices; and prohibits excavation or construction within capped and other areas without prior agency approval. For more information, see the covenant under “Reports, Documents, and Photographs”.

Engineering controls for the active portion of the facility will include a soil management plan covering any intrusive operations conducted within the TI Zone, and institutional controls restricting land use to non-residential purposes, prohibiting use or consumption of groundwater, and requiring further evaluation or mitigation of vapor intrusion prior to any building construction will be required.

Top of Page

Land Reuse Information at this Facility

NOVA Chemicals continues to use the active areas of the facility to manufacture polystyrene and other plastic feedstocks; inactive portions of the facility owned by the Lyondell Environmental Custodial Trust (West Landfill/Dravo Quarry Area and Raccoon Creek Area) and the Beaver County Corporation for Economic Development (East Landfill Area and Phthalic Anhydride Area) are unused

Top of Page

Site Responsibility at this Facility

Resource Conservation and Recovery Act (RCRA) Corrective Action activities at this facility have been conducted under the direction of EPA Region 3 with assistance from Pennsylvania Department of Environmental Protection.

Top of Page