2021 – Present: The Record of Decision (ROD) was issued in July 2021. The remedy is being implemented in accordance with the ROD.

2020: The Park-Euclid Working Group submitted the Proposed Remedial Action Plan (PRAP) for the Site to ADEQ for approval. Near the end of June, the PRAP was issued for a 90-day public comment period. The Park-Euclid Working Group also operated the soil vapor extraction system ERA at the Site and conducted soil vapor and groundwater monitoring and sampling at the site.

2019: The Park-Euclid Working Group is currently preparing the Proposed Remedial Action Plan (PRAP) for the site.

2017: In October, the Draft Feasibility Study (FS) Report was completed by the Park-Euclid Group and given final approval by ADEQ in November.

2016: The Final FS was submitted to ADEQ in the spring for approval and public comment.

2015:  In March 2015, The Park-Euclid Group submitted to ADEQ a draft FS and groundwater modeling reports to ADEQ for preliminary review.  ADEQ’s main concern was the uncertainty regarding the planned management of the treated water from the proposed groundwater pump-and-treat system.  Therefore, other management options for treated water options were evaluated, including discharge to a nearby wash and injection back into the regional aquifer.

An Early Response Action (ERA) soil vapor extraction (SVE) system for removal of volatile organic compounds (VOCs) from the LVZ operated from February 2015 through November 2015, removing approximately 1,900 pounds of VOCs from the LVZ, including 250 pounds of trichloroethylene (TCE).

2014: The Park-Euclid Group provided ADEQ with technical reporting concerning its groundwater modeling for the FS (site-wide) and SVE pilot testing for the lower vadose zone, sampled groundwater (perched and regional) and soil gas wells at the site, and installed two regional groundwater monitor wells to further delineate the toe and the eastern extent of the plume. The Park-Euclid Group completed its biotreatability bench-scale testing and determined that neither biostimulation (adding lactate) nor bioaugmentation (adding KB-1 microbial cultures) were viable for treating cis-1,2-dichloroethane (1,2-DCE), which is the dominant contaminant of concern in the perched groundwater.

The results of the Park-Euclid Group’s human health risk assessment for the FS indicated that there is no unacceptable risk to onsite workers or offsite residences from the migration of VOCs in shallow soil gas into buildings. (Shallow soil gas samples were collected onsite and offsite.)

At the end of 2014, the Park-Euclid Group presented ADEQ with an interim update on its remedial alternatives screening for the FS.

The Park-Euclid Group shut down the multi-phase extraction (MPE) system in April 2014. From the pilot phase, October 2011 through April 2014, approximately 110,500 gallons of water were treated and a total mass of approximately 3,392 pounds of VOCs were removed, along with approximately 7,250 gallons of diesel free-product. 

2013: The MPE system was restarted in January and ran continuously through February, after which it ran intermittently due to maintenance and overheating issues. Through the end of June, the MPE system removed approximately of 400 pounds of VOCs and 1700 gallons of diesel free-product. Groundwater sampling of all the monitoring wells occurred in February, with repeated sampling of the majority of wells in May and August. The FS work plan for future cleanup for the site was completed and approved in June and plans were made to install an additional regional aquifer monitoring well, upper vadose zone soil vapor sampling wells and a pilot SVE system for the lower vadose zone.

2012: As of the end of March, the MPE system had treated 8,565 gallons of water and removed a total mass of 542 pounds of VOCs. The MPE system operated routinely through September, and then was shut down for the remainder of the year awaiting additional permitting. Groundwater sampling occurred in January through March, and monthly from August to December.

2011: The MPE system was restarted in October. Groundwater sampling occurred in November and December. The final Remedial Investigation (RI) report was completed in November.

2010: In 2010, some of the potentially responsible parties at the Park-Euclid site signed an agreement to form the Park-Euclid Working Group to manage and fund remediation activities at the site with ADEQ oversight. The responsible parties at the site signed an agreement to form the Park-Euclid Group to manage and fund remediation activities at the site. Work plans were prepared and reviewed for groundwater monitoring and restarting the MPE system.

2009: ADEQ continued to work on completing the RI. No sampling was performed in 2009. Mission Linen operated the MPE system at the facility until June. A report detailing system operations was released in November. In this pilot phase of the MPE system, approximately 1,396 pounds of VOCs and 750 gallons of diesel free-product were removed, while treating 38,851 gallons of groundwater.

2008: Mission Linen completed construction of the MPE system to remediate contaminants including PCE in the perched aquifer and upper vadose zone. The MPE system became operational in April. Also in April, ADEQ installed a deeper sentinel well at the UAM-2 well location. This well is used for monitoring a deeper portion of the regional aquifer near the U of A wells.

2007: ADEQ selected a new consultant to perform site work. Periodic groundwater monitoring and sampling resumed along with monthly sampling of the UA production wells and ADEQ’s sentinel wells.

2006: In August, ADEQ completed the Remedial Objectives (RO) report following the completion of the public comment period. The RO for land use beneath Mission Linen is to restore soil conditions to the State’s non-residential soil remediation levels (SLRs). The RO for drinking water use of groundwater from the regional aquifer is to protect the use of the groundwater supply of the U of A and the City of Tucson from contamination from the site.

2004: In July, ADEQ released the draft RI report summarizing site characterization activities. Also, Mission Linen expanded the pilot SVE system and continued remediation of the shallow soils beneath the facility. An additional 420 pounds of PCE were removed from the shallow soils by the existing SVE system.

2002 - 2003: ADEQ installed an additional eight groundwater and three soil vapor monitor wells from May 2002 to February 2003. In February 2003, ADEQ conducted site investigation activities that focused on the sewer near the Mission Linen property.

2000 - 2001: In January 2000, three regional groundwater sentinel wells were installed south of U of A's Main Campus to monitor groundwater conditions up gradient of U of A’s wells. In February 2000, Environmental Protection Agency (EPA) informally delegated responsibility for the site to ADEQ through the RI/ FS stages.

In 2000, Mission Linen completed the installation of an SVE system beneath the facility at 301 S. Park Avenue. The pilot SVE system operated from June 2000 to August 2003 and removed approximately 6,000 pounds of PCE.

Since August 2000, monthly groundwater samples have been collected from the three sentinel wells. No PCE contamination above Aquifer Water Quality Standards (AWQS) has been detected in U of A’s water supply wells.

From November 2000 to February 2001, ADEQ installed 12 additional groundwater monitor wells to further characterize VOC and diesel contamination in the two aquifers underlying the site. ADEQ conducted site investigation activities within the vadose zone and shallow aquifer.

1999: The site was placed on the WQARF Registry with an eligibility and evaluation score of 51 out of a possible 120. In October, ADEQ initiated an RI. As part of the investigation, ADEQ began sampling two U of A water supply wells located down gradient from the site.

1998: EPA initiated site assessment activities in the area with the installation of two up gradient perched groundwater monitor wells.

1994: Mission Linen began investigating the regional groundwater aquifer including the examination of potential hydraulic connections between the perched and regional aquifers.

1993: Mission Linen conducted investigations that focused on the perched aquifer and the installation of a short-term pilot SVE system.

1992: Mission Linen conducted a Phase I investigation, which included soil gas sampling, groundwater sampling and the abandonment of an inactive water supply well.

1990: During an early ADEQ investigation of diesel contamination in the area, a groundwater sample was collected from a well on the Mission Linen property. Analysis of the sample indicated that contamination was present in the well and was a combination of diesel product and VOCs, including PCE, TCE and 1,2-DCE.