Arkla Terra Property

Overview

An underground storage tank refurbishment business ran at this Thonotosassa, Florida property from 1976 to 2006. Workers used solvents to clean tanks before repair, leaving soil and groundwater contaminated with tetrachloroethylene (PCE) and trichloroethylene (TCE). The U.S. Environmental Protection Agency (EPA) added the site to the National Priorities List (NPL) on April 9, 2009, after private water wells in the area were found to be affected.

PCE and TCE are industrial solvents. Exposure to very high concentrations of either can cause dizziness, headaches, nausea, confusion, and unconsciousness. TCE is classified as a human carcinogen by both the EPA and the International Agency for Research on Cancer (IARC). The main exposure concern has been drinking water drawn from private wells near the site, in the area between Ohio Avenue and Joe Roberts Road.

The EPA took several steps to address the contamination. Between 2012 and 2013, the agency used electrical resistance heating to warm the soil in the source area and boil off 1,491 pounds of PCE. Hillsborough County and the EPA also extended municipal water lines to connect affected homes and businesses to the public water supply. Water connections for residential and commercial properties were completed by December 2020. A final cleanup plan, called a Record of Decision (ROD), was signed on August 29, 2018. It requires ongoing groundwater monitoring, water line connections, and deed restrictions to prevent new well installation in the contaminated area.

The site reached ready-for-anticipated-use status on July 19, 2021, meaning cleanup is protective for reasonably expected future uses and necessary controls are in place. Physical construction was completed December 18, 2020. Groundwater quality has improved, with PCE concentrations declining through natural attenuation. Land use controls prohibit drinking water wells on-site, though irrigation wells are still permitted. The Southwest Florida Water Management District and local authorities enforce these controls. Long-term monitoring continues, and the site remains on the NPL. A Five-Year Review was conducted on December 1, 2025, to confirm the remedy continues to protect human health and the environment.

Community members can stay informed through EPA fact sheets, public notices, and public meetings. Site documents are available at the Thonotosassa Branch Library at 10715 Main Street in Thonotosassa, Florida. Residents with questions can contact Angela Miller, the Community Involvement Coordinator, or Beth Walden, the Remedial Project Manager.