The Le Mars Coal Gas site (Site), in Le Mars, Plymouth County, Iowa, is a non-time-critical removal action. The Site is a former manufactured gas plant (FMGP). The U.S. Environmental Protection Agency (EPA) is removing coal-tar waste containing benzene, toluene, ethylbenzene, xylenes (BTEX) and polycyclic aromatic hydrocarbons (PAHs) from the Site area. The Action Memorandum for the Site was signed on September 26, 2003. The complete Administrative Record for the Site can be found at the record repository located at the Le Mars Public Library.
On Wednesday, May 12, 2004, an Action Memorandum Amendment was signed allowing all of the contaminated soil to be sent off-site to a thermal treatment facility.
The Site is located at 331 1st Street Northeast, Le Mars, Plymouth County, Iowa, and is a 1.6-acre, right-triangle-shaped property, which is bordered on the northwest by the Union Pacific and Canadian National railroads, on the east by 4th Avenue Northeast and on the south by 1st Street Northeast. The area surrounding the Site is occupied by residential and commercial properties. The Site is in Section 9, Township 92 North, Range 45 West (U. S. Geological Survey [USGS] 1985). The geographic coordinates of the Site are latitude 42°47'40" north and longitude 96°09'37" west.
There have been over 11,536 tons of coal-tar-contaminated soil sent to the thermal desorption facility in Cedar Rapids. Up to 30 trucks are being loaded with the material 6 days a week.
Work hours at the Site have been extended, starting at 6:00 a.m. each day, while the "load out" of contaminated soil continues. Most ending times have generally been around 6:00 p.m. There have been occasions when there has been limited work activities on Sundays during the project. Considerations have been given toward the community when making those decisions, including disruptions to local church traffic.
The structure of the work crews is comprised of an excavation crew and a backfill crew. A portion of the backfill crew is located at a separate location in Le Mars, approximately 2 miles away. The backfill is being provided to the EPA by the city of Le Mars. A "sheep foot" compactor is being utilized to compact the replaced clean fill to meet state compaction regulations. A local engineering firm is being used in a sub-contracting role to perform compaction tests as well as other services, including, assuring proper grade elevations.
On Wednesday, May 12, 2004, an Action Memorandum Amendment was signed allowing all of the contaminated soil to be thermally treated.
This amendment was needed due to the denial of three Iowa Subtitle D landfills in accepting the coal-tar-contaminated waste. There is one Nebraska Subtitle D landfill located in Jackson that is willing to accept the waste. However, the Nebraska Department of Environmental Quality (NDEQ) requires a public notification period that would result in Site personnel de-mobilizing at a significant cost to the EPA and also would present a hardship to the city of Le Mars Street Department personnel who have re-located during the removal action. Also, due to seasonal fluctuations, the EPA is not encountering the water table at 14 feet below ground surface (bgs). This seasonal fluctuation was not entirely unexpected but was also noted in the amendment.
Continued excavation of contaminated soils will continue. Approximately 90% of the area has been excavated at this time. Continued replacement of clean backfill will be on-going.
In communications with the DCI Environmental Inc. representatives, the thermal desorption unit has not been activated yet to treat the contaminated soils. Their plan is to wait until they have received all of the material before they activate their unit. Possible plans by EPA include a visit to the thermal unit's location when the treatment of the soil from the Site begins.
A complete round of air sampling was initiated on Friday, June 4, 2004, utilizing the Summa canisters to measure benzene. Close attention is being given to the air quality both on and off of the Site. The placement of these sample stations are based on sensitive population(s) location and prevailing wind patterns.
This is the third round of air sampling that will be sent for laboratory analysis in addition to the baseline air sampling that was performed before excavation started. Daily "real-time" air monitoring is also on-going.
All of the results have been given to the EPA Regional Toxicologist, Agency for Toxic Substances Disease Registry, and the Iowa Department of Public Health officials for their review and monitoring.
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