Apache Powder Company

Superfund Site | Apache Powder Company: Page 2 of 2

Action Taken

The EPA and ADEQ have completed investigations of the northern area groundwater contamination and chose monitored natural attenuation (MNA) as a final remedy enhancement to the existing remediation system. All remedies for the northern area are now in place and long-term operation and maintenance of these remedies has begun. The design and implementation of the MNA remedy for the southern area groundwater was completed in fall 2007. In addition, institutional controls that are called for in an amended Record of Decision (ROD) were in place by fall 2008. Native soil covers have been constructed for former pond areas.


Additional on-going remedial work continues at ANPI, the site has three major ongoing remedial actions as identified in the 2008 Preliminary Close-Out Report. The current selected remedies are:

Northern Area Groundwater 

Use of a constructed wetland to treat water coming from a nitrite-contaminated shallow aquifer, monitored natural attenuation (MNA) for groundwater at the end of the plume outside the capture zone, and institutional controls (ICs).

Apache Nitrogen Products Inc. (ANPI) continues to work towards accelerating the groundwater cleanup in the Northern Area Remediation System (NARS). Actions taken in 2018 include the following:

Former pilot test extraction well began pumping to the treatment lagoons (wetlands) in July 2018.

A geophysical study (Electrical Resistivity and Induced Polarization (IP)) was conducted in July 2018 to better understand the area geology within the NARS. The information from the study report issued in September 2018 was used to determine the locations for additional drilling and extraction well construction which began in November 2018 with scheduled completion in February 2019.

Southern Area Groundwater
Continuation of long-term monitoring and ICs for the Perched System and shallow aquifer.

Contaminated Soils 
Excavation and off-site disposal or on-site treatment or encapsulation, including ICs for other contaminated soils detected during confirmatory soil sampling in the Legacy Soils Area. ANPI will submit the final Legacy Soils Area Remedial Action Report once all the remaining work is completed (projected completion 2019).

Community Involvement Activities

Public meetings are organized for site issues where there is considerable public interest.

As required by the ROD for this site, Apache Nitrogen Products, Inc. provides semi-annual notices to the surrounding community regarding the extent of groundwater contamination and the danger of using this water for drinking water. Apache also keeps an inventory of private well use in the area, and they monitor/track groundwater drilling in the area.

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