Revised On: Jan. 28, 2024 - 11:45 a.m.

2018 – 2022: NXP continued to operate and maintain the groundwater pump and treat system as the early response action (ERA). Groundwater samples and water level data were collected by NXP in April and October each year. NXP completed a residential indoor air investigation and a soil gas investigation near the former source area to fulfill data gaps as part of the Feasibility Study (FS). Indoor air results from homes that elected to participate in the investigation, as well as soil gas results, are presented in the FS. The FS was finalized in March 2022.

2016 – 2018: NXP (formerly Freescale Semiconductor) continued to operate and maintain the groundwater pump and treat system as the ERA. Groundwater samples and water level data were collected by NXP in April and October each year. The Remedial Investigation Report, Remedial Objectives Report, and Feasibility Study Work Plan were finalized in November 2018.

2015: Freescale continued to operate and maintain the groundwater pump and treat system as the ERA based on a Consent Order with ADEQ. Freescale and ADEQ also agreed to terms on a Consent Order for Freescale to perform the Remedial Investigation and Feasibility Study for the site. Groundwater samples and water level data were collected by Freescale in April and October.

2014: The ERA groundwater pump and treat system began operation in November 2013. Freescale submitted a Site Operation and Maintenance Plan for the ERA which ADEQ approved in October 2014 after a 30 day public comment period. Freescale will conduct operation and maintenance of the system based on a pending agreement with ADEQ. A Consent Order for the Remedial Investigation and Feasibility Study reports is under negotiation between ADEQ and Freescale. Groundwater samples and water level data were collected by Freescale in April and October.

2013: Freescale plans to complete construction of the groundwater pump and treat system in the fall.  Freescale will conduct operation and maintenance of the system based on the pending agreement with ADEQ.  Groundwater samples and water level data were collected by Freescale in April and another set will be collected in October. Freescale is providing monthly progress reports to ADEQ on the status of the ERA.

2010 – 2012: Freescale entered into a Consent Order with ADEQ on April 22, 2011 to design and implement an ERA. Freescale collects groundwater samples and water level data from 41 monitor wells in April and October. Freescale and Clear Creek Associates continue to work on the permitting and environmental clearances required to construct the groundwater pump and treat system. Freescale is also providing monthly reports to ADEQ on the progress of the ERA.

2009: Freescale prepared a work plan describing the installation and development of two groundwater extraction and two groundwater monitoring wells on the north side of the Grand Canal. The four wells comprise the first phase of the ERA to contain and control groundwater contamination in the area.

2008: Freescale was involved in negotiations with the various landowners of the land adjacent to the Grand Canal that would be the site of the extraction and treatment system.

2007: Freescale tentatively selected the use of a groundwater extraction and treatment system to address the contaminant plume. The system will employ granular activated carbon to remove contaminants from the groundwater prior to discharge to the Grand Canal. 

2006: Freescale agreed to implement an ERA evaluation to evaluate potential impact to a downgradient SRP well for the site. The maximum PCE and TCE levels present in the groundwater were 46 µg/L and 770 µg/L, respectively. 

2005: Freescale Semiconductor, Inc. (a successor company to Motorola) installed additional monitor wells during the Third Quarter to the west and southwest of TCE contaminant plume to further delineate the extent of groundwater contamination. Following installation and sampling of these wells, an ERA evaluation was conducted.

2004: The site was placed on the WQARF Registry on June 2nd, due to the presence of PCE and TCE in the groundwater at levels that exceeded the Arizona Aquifer Water Quality Standard of 5.0 mg/l. The eligibility and evaluation score for placement on the WQARF Registry was 40 out of 120.

1997: Following an on-site confirmation soil gas investigation, ADEQ granted a soil No Further Action determination to Motorola.

1993 – 1996: The following ERA activities have been conducted by Motorola:

• Abandonment of on-site drywells (1993)
• Pilot scale bioremediation test operations
• On-site soil vapor extraction system installed (1994)
• On-site soil excavation (1996)
• 1989: The site was originally investigated as part of the Motorola 52nd Street National Priorities List Superfund Site. However, groundwater data indicated there were two separate and distinct areas of contamination. Therefore, the site was disassociated from the larger Motorola 52nd Street site.
  
  

1985: Motorola began investigation of the 56th Street facility. Investigations were conducted in stages and included:

• Investigation of possible source locations
• Soil borings and sampling program
• On and off-site soil gas investigations Off-site soil gas investigation identified five potential source areas for volatile organic compound (VOC) contamination
• Installation of 39 groundwater monitor wells (including three multi-port monitor wells)
• Groundwater sampling program (currently semi-annual)
• Aquifer tests and groundwater modeling
• Investigation of inorganic constituents found in groundwater