Patrick Bayou

Overview

Patrick Bayou is a waterway in Deer Park, Texas that feeds into the Houston Ship Channel. The U.S. Environmental Protection Agency (EPA) added it to the National Priorities List (NPL) in September 2002 after investigations found that contaminated sediments posed a threat to downstream fisheries. The bayou has the highest dioxin concentrations among locations studied along the Ship Channel.

Contaminants in the sediments include mercury, polychlorinated biphenyls (PCBs), dioxins, polycyclic aromatic hydrocarbons (PAHs), lead, chromium, copper, nickel, selenium, zinc, hexachlorobenzene (HCB), and bis-2-ethylhexyl phthalate. The main risk is people ingesting or touching these contaminants. Fish advisories are in place for children and women of childbearing age due to dioxin levels, and for the general public regarding PCBs and dioxins. Current assessments show human exposure is under control, meaning no unacceptable pathways exist for people to contact the contaminants. Groundwater migration is also under control.

Three companies, Shell Oil, Lubrizol Corp., and Occidental Chemical Corp., are conducting a Remedial Investigation and Feasibility Study (RI/FS) under an agreement with the EPA. That study began in January 2006 and is expected to conclude between December 2027 and February 2028. It covers one operable unit (OU-01) focused on sediment. In November 2022, the EPA approved an Engineering Evaluation and Cost Analysis (EE/CA) to plan a Non-Time Critical Removal Action (NTCRA). That removal action targets sediments with elevated mercury and PCBs. It aims to reduce direct contact with contaminants and limit transport of polluted material into the Houston Ship Channel. The removal action is estimated to begin between October and December 2026, with completion expected between December 2027 and February 2028. Physical construction of the cleanup remains incomplete, and not all cleanup goals have been met.

A Record of Decision (ROD), which will document the final long-term cleanup approach, is estimated for the same late-2027 to early-2028 timeframe. Remedial design is scheduled to start between March and May 2027.

Community members can contact the EPA Community Involvement Coordinator with questions or to join the site email list. Updates are also available on EPA Region 6 social media platforms. The Texas Commission on Environmental Quality (TCEQ) also supports the site and can be reached through its project manager and community relations staff.