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Congressional District # 11


EPA ID# ILD005468616
Last Updated: September, 2011

Site Description

The Ottawa Township Flat Glass (OTFG) site is located in Naplate, La Salle County, Illinois, about 60 miles southwest of downtown Chicago. The OTFG site is also known as the “Libbey-Owens-Ford (LOF) Plants 5&7” site. The 228-acre site consists of the property containing a glass manufacturing facility ("Plant #5" (active) and "Plant #7" (currently inactive)) located on the north side of the Illinois River; and former silica sand quarries, wastewater disposal areas, and a 56-acre undeveloped parcel of land. It also includes additional former silica sand quarries and wastewater disposal areas across from the facility on the south side of the river.

The manufacturing plant has been making flat glass products since about 1907.  Arsenic trioxide was a minor ingredient in the manufacturing process from 1907 until 1970 when its use was discontinued.  The final step in the manufacturing process involved grinding and polishing cast glass with fine silica sand and water.  The process generated a waste slurry containing mostly sand, water, and glass  particles (containing arsenic) which was discharged into the former quarries for settling of solids and discharge of overflow water into the Illinois River.  The slurried waste in the settling areas contains appreciable levels of arsenic and is a source of arsenic contamination in local area groundwater as well as being a direct contact or ingestion threat to human and ecological receptors.

EPA has divided the OTFG site into four segments, called "operable units" (OU), for ease of investigating and addressing site contamination. These include the Residential Soils (OU #1), Illinois River Sediment (OU #2), Groundwater and Source Areas south of the river (OU #3), and Groundwater and Source Areas north of the river (OU #4).

Pilkington North America, Inc. (PNA) purchased the glass manufacturing facility from LOF in 1986, about 16 years after the use of arsenic in the glass-making process was discontinued.  PNA continues to operate the glass manufacturing plant to date. 

Site Responsibility

The OTFG site is currently being addressed through federal oversight of potentially responsible party actions.  Previous activity at the site was conducted under the lead of the state.

To date, under EPA oversight, Pilkington North America (PNA) has performed a time critical removal action, a remedial investigation, and several baseline human health and ecological risk assessments.  PNA is conducting work at the site under the Superfund Alternative Approach.  The OTFG site is not listed on the National Priorities List, however, PNA has agreed to conduct a remedial investigation and feasibility study consistent with Superfund program guidance and regulation.

Threats and Contaminants

Arsenic is the contaminant of concern at the site.  It is a poison in high doses and a potential human carcinogen through prolonged exposure to much lower amounts, although it may also be an essential micro-nutrient.  People or animals that come into contact with arsenic-contaminated soil or that drink arsenic-contaminated water could be at risk, depending on duration and arsenic exposure levels as well as other factors.

Elevated levels of arsenic were found in the soil of the yards of two residences in Naplate near the glass plant, prompting investigation of almost all yards within the village.  The former quarry settling areas are located adjacent to the Illinois River, causing a concern that river sediment may be contaminated with arsenic.  Arsenic is found at very high levels in the settling areas and in the shallow groundwater aquifer beneath the settling areas, but it has not impacted Naplate's drinking water supply (derived from a separate aquifer). 

Very high levels of arsenic in residential yards could be an immediate and/or long-term threat to human health through ingestion, inhalation, or dermal absorption.  Arsenic contamination in river sediment could impact ecological receptors.  Arsenic in the settling areas could be an immediate and/or long-term threat to human health and the environment through ingestion, inhalation, or dermal contact.  The arsenic-contaminated groundwater is a potential threat to human health through ingestion should the contaminated water be used for potable purposes.

Cleanup Progress

Illinois EPA initially managed site investigations from the early 1980s until it referred the site to U.S. EPA in the late 1990s.  U.S. EPA reached an agreement with PNA in September 2001 whereby the site would be handled as if it were listed on the Superfund National Priorities List but would not have to go through the listing process (Superfund Alternative Approach).  U.S. EPA and PNA signed an Administrative Order on Consent ("AOC") under which PNA agreed to conduct a remedial investigation ("RI") and feasibility study ("FS") at the site under U.S. EPA oversight.  Remedial investigation activities have been conducted to determine the nature and extent of (arsenic) contamination in area groundwater, soil, and sediment.

Residential Soils

PNA conducted soil sampling in a few Naplate residential areas in late 2002 and discovered elevated levels of arsenic in shallow (0 to 6 inches) and deep (greater than 12 inches) sampling points on two lots (417 and 419 22nd Ave.) located close to the factory.  Soil arsenic levels were found to be as high as 44,800 milligrams per kilogram (mg/kg or "parts per million" or "ppm") on parts of these lots.  (EPA’s removal action level for arsenic concentration in residential soil is about 100 ppm.)  It was later determined that settling area fill material had been removed from the facility and used to fill in low spots on two residential lots so that homes could be built.

PNA, under EPA oversight, began a time-critical removal action at the two yards in December 2003, excavating arsenic-impacted soil above about 20-40 ppm.  PNA safely excavated a total of 3,325 cubic yards of soil and slurry material and disposed of it in an off-site landfill.  While this work was being done the residents of the two homes were temporarily relocated to a local hotel.  After sampling the edges and bottoms of the excavations to confirm that all impacted soils had been removed, PNA placed clean soil backfill into the excavations and reseeded the lots.  The removal action was completed in June 2004.  The homes were also found to have above-normal levels of arsenic-laden dust inside and PNA performed an interior cleanup action in 2004 for the home at 419 22nd Ave. and in 2006 for the home at 417 22nd Ave. to reduce the interior arsenic levels to safe levels.

PNA also expanded the residential sampling program in 2003 to include additional testing at residences located very near the area of the two impacted properties.  The residential soil sampling program was expanded again in fall 2005 to cover almost all of the lots in the village.  Over 2000 soil samples were taken by PNA from about 210 Naplate residential lots and analyzed for arsenic.  About 21 residential lots and 3 commercial properties were not sampled either because access was not granted or there were no exposed soil areas to sample.  Results of the soil analyses were tabulated and presented in the Remedial Investigation Report for the Residential Soils Operable Unit (August 2007).  Results indicate that slurry material has not been placed as fill on any other village lots and that no immediate health threats are present.

The arsenic concentration trends in the residential area soil samples showed that the composite soil arsenic levels were less than or equal to 10 ppm in the majority (approximately 65 percent) of the sampled areas.  Another 33 percent of the sampled areas had composite soil arsenic concentrations of 10 ppm to 20 ppm.  The composite soil arsenic levels of 98 percent of sampled areas are consistent with the state’s published background level of 11-13 ppm.  Since 11-13 ppm is an average background soil arsenic level due to anthropogenic sources, EPA believes it is reasonable to assume that some areas would be slightly higher than 11-13 ppm arsenic and some lower.  Hence a range of 10-20 ppm is considered background. 

The last 2 percent of the sampled areas, or seven residential yards and one area in an alley, had composite arsenic concentrations of 20 ppm to 30 ppm or more.  PNA conducted a final removal action in these 8 yards in September 2008.  Soil was removed from around the sampled areas that exceeded 50 ppm arsenic and taken off site for disposal.  The cleanup resulted in the composite arsenic levels for these 8 properties to fall within the composite arsenic values for the rest of the Village of Naplate.

The health risks associated with the remaining residential soil arsenic levels were determined to not exceed cancer-causing and non-cancer-causing levels.  In September 2008 EPA selected "No Further Action" as the final cleanup approach for the residential soils.


PNA and others began testing the Illinois River environment for arsenic before the 2001 RI/FS AOC was signed.  PNA collected sediment samples and conducted bathymetric surveys.  Data indicated an area of potential concern along the north side of the Illinois River next to the site.  Over 100 sediment samples were taken from along the north shoreline, with arsenic values ranging from non-detect to 428 ppm.  The average was about 50 ppm, although half the samples were less than 18 ppm.  The above-background values indicate that the sediment along the north shoreline is impacted by arsenic contamination from the site.

PNA took 33 sediment samples upstream of the OTFG site.  These samples were considered to be background samples or those unaffected by the site.  Arsenic values ranged from not detected (ND) to 13 ppm, averaging about 5 ppm.

Over 100 samples were taken from the south side of the river near the glass plant location and also downstream.  Arsenic values ranged from ND to 29 ppm, averaging about 4 ppm, indicating that the sediment in these areas is not impacted by arsenic from the site.

The U.S. Geologic Survey sampled sediment in the Illinois River over the last 10 years or so. According to a USGS on-line database, samples taken a few miles upstream (near the Marseilles lock-and-dam) had arsenic values ranging from 1 ppm to 7 ppm.  Downstream sediment samples (from the Starved Rock lock-and-dam area) had arsenic values at about 1 ppm.  These data indicate that the sediment in these areas is not impacted by the site.

PNA also looked at water quality data for the river from samples taken by others in the 1990s.  These sample results showed that there were no measurable levels of arsenic from the site in river water.

PNA conducted radioisotope studies on the north shorline-area sediment.  These data indicate that the sediment deposit was laid down in the 1950s.  It also suggests that the deposit is stable and not subject to wash out by yearly flooding.

Illinois EPA conducted bioassay studies on the north shoreline-area sediment in about 1990.  Data indicated no acute toxicity effects from the sediment on the sensitive test organisms.  PNA conducted tests in 2002 on benthic organisms and data showed some chronic effects; however, there was no discernible difference between upstream and downstream chronic toxicity effects on test benthic organisms.  Thus, no fish sampling was done because literature suggests that health impacts on fish occur at arsenic levels that are at least an order-of-magnitude above that of benthic organisms.

EPA concluded that the arsenic-impacted sediment in the Illinois River along the north shoreline next to the site is very stable – it wouldn’t be prone to scour by river water, it has very little or no effect on river water quality, and that it is little/not toxic (attributable to arsenic) to aquatic organisms.

The human health risks associated with the sediment arsenic levels were calculated to not exceed cancer-causing and non-cancer-causing levels.  Therefore, EPA selected "No Action" as the final cleanup approach for the Illinois River Sediment, as documented in the September 2008 Record of Decision (ROD).

Source Areas and Groundwater

PNA installed and sampled a number of groundwater monitoring wells in 2002-04 in and around the site and sampled nearby private wells to determine the nature and extent of groundwater contamination.  Results indicate that there are two groundwater aquifers of immediate concern.  The upper aquifer, the St. Peter Sandstone, is a regional unconfined aquifer that has been impacted by arsenic contamination from the site.  Data indicate that the lower aquifer, the New Richmond Sandstone, has not been been impacted by arsenic contamination.  Between the two aquifers lies the Shakopee Dolomite, a 150-200 foot thick aquitard that forms an effective barrier between the St. Peter Sandstone and New Richmond Sandstone.  Arsenic levels in the St. Peter Sandstone range from a few parts per billion ("ppb") at the edges of the contaminant plume to several ppm in the center, about 400 times higher than the maximum contaminant level for arsenic (10 ppb) under the Safe Drinking Water Act.  The St. Peter Sandstone, however, is not used for potable purposes in the site area.  The Village of Naplate public water supply well draws water from the deeper New Richmond Sandstone aquifer and thus is not at risk of arsenic contamination.

PNA collected soil samples on the facility property and results indicate that elevated levels of arsenic are in the settling areas, primarily the former quarries and waste disposal areas where the polishing slurry was discharged.  These areas act as sources of arsenic contamination in the upper aquifer.  A human health and ecological risk assessment has been drafted to evaluate arsenic impacts; the risk assessments should be final by the end of 2011.  

An interim, September 29, 2010, Record of Decision (ROD) was signed by EPA for OU 3, which includes groundwater and contaminant source areas on the south side of the river.  The data indicated that an immediate action needed to take place prior to a final ROD.  The Interim remedy consists of the redirection of storm water flow away from the arsenic-laden quarries; institutional controls to preven future residential development and potable well installation in the affected aquifer; municipal water supply; and the monitoring of ground water quality over time.  Currently, EPA and PNA are negotiating an agreement for the design of the selected remedy.

Future Work

Future work includes an FS for OU4, which includes source areas and groundwater on the north side of the river.   

Success Story

Under EPA oversight, PNA safely and successfully cleaned up the two highly-impacted residential lots in 2004 and cleaned the interiors of the homes shortly thereafter.  In 2008 PNA safely and successfully removed additional soil from the residential areas to bring down composite arsenic levels to equal those found on the rest of the lots in Naplate.  The results of the soil sampling and cleanup work allowed EPA to issue a "No Further Action" ROD for the residential soils operable unit.  An Interim Record of Decision has been signed for OU3, groundwater South of the Illinois River.

Community Involvement

On May 24 through 26 EPA conducted community interviews for the Community Involvement Plan (CIP).  EPA is currently developing CIP for this site.  Once the plan is complete it will be sent to the information repostiories and will be available online.

Property Reuse

The 56-acre undeveloped parcel that is considered part of the site has been sampled and shown to be not impacted by arsenic on the surface.  The property likely is eligible for reuse, although it is likely that groundwater-use restrictions may have to be placed on the land because arsenic is found in the groundwater beneath the site.

The interior of the impacted residences at 417 and 419 22nd Ave. have been cleaned of arsenic residue and are available for reuse.

It is expected that property use (indutrial and residential) in and around OU3 will remain the same.


Remedial Project Manager, U.S. EPA
nefertiti simmons (simmons.nefertiti@epa.gov)
(312) 886-6148



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