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 Environmental Protection Agency (EPA) is removing coal tar wastes 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.
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.
While excavating north of the main, street department building, it was determined that the 12,000 gallon underground storage tank (UST) contained approximately 700 gallons of contaminated unleaded gasoline.
On-scene coordinator (OSC) Dan Garvey coordinated efforts with Mr. Bryon Whiting, Iowa Department of Natural Resources (IDNR), Underground Tank Inspector, concerning information pertaining to state regulations for USTs. Mr. Whiting commented that the state requires notification when the tanks are pulled. OSC Garvey confirmed that the notification requirement would be satisfied if the state was placed on the distribution list for the weekly POLREPs generated from the Site.
Also, Mr. Whiting provided OSC Garvey with information concerning sludge haulers to dispose of the contaminated gasoline and steel recyclers for the USTs themselves.
Additionally, Mr. Michael Leat, IDNR, visited the site and received a site orientation. Mr. Leat assisted OSC Garvey throughout the day, contributing with input regarding numerous decisions that were on-going.
Approximately 14 feet of contaminated soil requires excavation down to the water table. Some de-watering may be necessary. In addition, Gas Holders A and B, the tar well, the 12,000-gallon UST and one 2,000-gallon UST will also be removed.
The following listed steps are planned during the removal action to alleviate the human health risk posed by the Site:
a. Air monitoring of removal action construction
b. UST and product removal
c. Excavation of the on-site soil source area
d. Off-site thermal treatment of highly contaminated soil
e. Off-site disposal of non-hazardous soil and debris in a Resource Conservation and Recovery Act(RCRA) Subtitle D landfill
f. Backfilling with off-site soil and site restoration
A local engineering firm, Schlotfeldt Engineering Inc. is making daily visits to the site to guide the excavation along the buildings. Special excavation techniques are being implemented to assure the integrity of the building and the safety of the work crew. The engineering firm is also planning to survey grade elevations for drainage and to verify the railroad property is not affected by the action.
A complete round of air sampling has been initiated on Thursday, April 30, 2004. High volume air samplers (PS1) and Summa canisters are being utilized. The sample period will be 72 hours. The analytical turnaround time is 3 days.
A significant event that occurred late in the week is the bidding process that is on-going for disposal facilities to receive the contaminated soil. All of the bids were required to be submitted by noon on Friday, April 29, 2004. An intensive review commenced Friday afternoon to review the various proposals.
Some of the overburden is being stockpiled and sampled. If all of the analytical parameters are met, the soil will be used as backfill.
Analytical results received late Friday afternoon on April 30, 2004 for the backfill source that is being provided by the city of Le Mars indicated that the soils were acceptable for Site use.
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