A field Investigation will be conducted at IRP Sites No. 7 (Dry Well off Corrosion Control Building) and No. 8 (Dry Well off Composite Maintenance Building), Montana Air National Guard, Great Falls International Airport, Great Falls, Montana. The Remedial Investigation (RI), completed in May 1997, recommended that an Engineering Evaluation/Cost Analysis be performed at Sites 7 and 8 to determine the significance of the groundwater contamination, and what remedial measures, if any, should be taken. The field investigation will consist of installing four (4) monitoring wells at each site, collecting and analyzing groundwater from each well, and measuring hydraulic properties of the groundwater. The objectives of this investigation will be to assess the extent of groundwater contamination, to determine the potential risk of the contamination to human health and the environment, and to evaluate removal action alternatives.

A Remedial Investigation was conducted at the Great Falls Air National Guard Base during April, May, and July 1996. During the period four IRP sites were investigated (IRP Sites 1, 6, 7, and 8). The investigation consisted of drilling 14 soil borings and installing 10 monitoring wells. At Sites 1 and 6, no contaminants in the soil or groundwater were found above State and Federal cleanup levels; and a Decision Document to support no further action is recommended. At Sites 7 and 8, no contaminants were found in the soil above State and Federal cleanup levels; and a Decision Document to support no further action with respect to soil contamination is recommended. At Sites 7 and 8, groundwater contamination above State and Federal cleanup levels was detected. The contamination included petroleum hydrocarbons, chlorinated solvents, and dissolved metals. It is recommended that an Engineering Evaluation/Cost Analysis be prepared to evaluate remedial alternatives for the groundwater at Sites 7 and 8.

A Remedial Investigation was conducted at the Great Falls Air National Guard Base during April, May, and July 1996. During the period four IRP sites were investigated (IRP Sites 1, 6, 7, and 8) . The investigation consisted of drilling 14 soil borings and installing 10 monitoring wells. At Sites 1 and 6, no contaminants in the soil or groundwater were found above State and Federal cleanup levels; and a Decision Document to support no further action is recommended. At Sites 7 and 8, no contaminants were found in the soil above State and Federal cleanup levels; and a Decision Document to support no further action with respect to soil contamination is recommended. At Sites 7 and 8, groundwater contamination above State and Federal cleanup levels was detected. The contamination included petroleum hydrocarbons, chlorinated solvents, and dissolved metals. It is recommended that an Engineering Evaluation/Cost Analysis be prepared to evaluate remedial alternatives for the groundwater at Sites 7 and 8

A Remedial Investigation was conducted at the Great Falls Air National Guard Base during April, May, and July 1996. During the period four IRP sites were investigated (IRP Sites 1, 6, 7, and 8). The investigation consisted of drilling 14 soil borings and installing 10 monitoring wells. At Sites 1 and 6, no contaminants in the soil or groundwater were found above State and Federal cleanup levels; and a Decision Document to support no further action is recommended. At Sites 7 and 8, no contaminants were found in the soil above State and Federal cleanup levels; and a Decision Document to support no further action with respect to soil contamination is recommended. At Sites 7 and 8, groundwater contamination above State and Federal cleanup levels was detected. The contamination included petroleum hydrocarbons, chlorinated solvents, and dissolved metals. It is recommended that an Engineering Evaluation/Cost Analysis be prepared to evaluate remedial alternatives for the groundwater at Sites 7 and 8.