The former Carriage Cleaners dry cleaner occupied 2110 & 2112 Franklin Street in Bellevue, Sarpy County, Nebraska. Carriage Cleaners operated as a dry cleaner and initiated hazardous waste reporting to Nebraska Department of Environment and Energy (NDEE) in 1986 under the Resource Conservation and Recovery Act (RCRA). Waste generated at the Site was PCE and cartridge filters. Approximately 4,000 to 18,000 pounds of waste PCE was generated at Carriage Cleaners from 1988 to 1992. Carriage Cleaners had a contractual arrangement with Safety Kleen to remove the waste PCE for disposal. In October 1995 the NDEE was notified that Carriage Cleaners was no longer doing business and had filed for Chapter 7 Bankruptcy.
Phase I and Phase II Environmental Site Assessments (ESAs) were completed for the Carriage Cleaners property in 2017 by Thiele Geotech, Inc. on behalf of the current property owner. A Supplemental ESA was completed in July 2018 by Olsson Associates on behalf of the NDEE. These investigations included sampling of soil, groundwater, soil gas, sub-slab soil vapor, and indoor air. PCE and trichloroethylene, or TCE, were detected in all media above their respective EPA Regional Screening Levels, or RSLs, or Removal Management Levels, or RMLs.
The NDEE conducted vapor intrusion sampling adjacent to, and in the vicinity of, the suspected source area. Sampling documented PCE-contaminated soil gas in the subsurface soil vapors as high as 1.1 million micrograms per cubic meter (µg/m3), and PCE in the indoor air as high as 130 µg/m3. Based on sampling conducted thus far, one residential property and five commercial properties meet criteria that either exceed Removal Management Levels (RMLs) or have the potential to exceed RMLs in indoor air. Indoor air concentrations at these properties present, or may present, an immediate human health risk and exceed the established indoor air and sub-slab soil gas screening and RMLs for PCE and/or TCE
The NDEE submitted a Request for Federal Action, dated July 12, 2019, requesting that EPA evaluate the following types of actions: (1) Mitigate vapor intrusion into residences and businesses that NDEE determined have either indoor air or sub-slab vapor sampling results exceeding applicable risk-based standards for protection of human health, (2) conduct additional indoor air and sub-slab sampling within the extent of contamination, and (3) conduct additional soil and groundwater sampling to define and control the source(s) of contamination.
The EPA issued a Time-Critical Action Memorandum on August 26, 2019 to mitigate the immediate threats to public health, welfare and the environment posed by exposure to volatile organic compounds that may migrate into homes and commercial buildings through vapor intrusion. Intended response actions include the assessment and mitigation of sub-slab and indoor air contamination above applicable action levels, as well as additional sampling to delineate the magnitude and extent of contamination in the source area(s) and down-gradient, and to implement source attenuation measures if deemed warranted and practicable.