The MARCO (Mid-America Refining Co.) site (Site) is an industrial site located at 1201 North Santa Fe, Chanute, Neosho County, Kansas. The public land survey description is the SE ¼ of Section 17, Township 27 South, Range 18 East, Neosho County, Kansas. The Site is surrounded by commercial & industrial property owned by Ash Grove to the north, commercial & industrial property to the east, including a metal scrap yard, and mixed commercial & industrial, city-owned, and residential properties to the south and west.
Crude Oil processing occurred at the MARCO site from 1934 until the facility was shut down in 1981. Documents dating back to as early as 1940 show complaints regarding waste oil being allegedly discharged into Village Creek and the Neosho River, along with numerous releases and spills. Separate site investigations conducted by KDHE and the EPA during the late 1980s and early 1990s identified the presence of corrosives, flammables, poisonous substances, mercury, and asbestos. Cleanup activities in the late 1990s included of the removal of storage tanks, mercury contaminated waste, solidified material from leftover sludge pits, and the excavation of petroleum contaminated soil.
Site sampling in the late 1990s found high levels of hydrocarbons and dissolved heavy metals contamination in the groundwater, including benzene, toluene, ethylbenzene, naphthalene, lead, cadmium, and arsenic. Soil samples were contaminated by chlorobenzene, 1,4-dichlorobenzene, naphthalene, benzene, and lead. Long-term groundwater monitoring started in 2000, and as of the last sampling in November 2021, monitoring wells contain contamination that exceed their respective RSK values for Total Petroleum Hydrocarbon – Low Range Hydrocarbons (TPS-LRH), TPH – Mid Range Hydrocarbons (TPH-MRH), TPH – High Range Hydrocarbons (TPH-HRH), benzene, naphthalene, and 1,2,4-trimethylbenzene.