Hazardous Waste Cleanup: Former Chevron Refinery Facility - Hooven, Ohio

On this page:

• Cleanup Status
• Site Description
• Contaminants at this Facility
• Institutional/Engineer Controls
• Land Reuse
• Site Responsibility

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Cleanup Status

The cleanup currently is undergoing what is called near-term Final Corrective Measures in some areas of the site while other areas are in the operation and maintenance phase. The near-term Final Corrective Measures deal with the most difficult portions of groundwater contamination through periodic ongoing high-grade pumping efforts. To date, that high-grade pumping, started in 2007, has removed 278,000 gallons of Light Non-aqueous Phase Liquids (LNAPL). This is a refined product, difficult to remove, which tends to float on top of the groundwater. The removal of Solid Waste Management Units (SWMUs) on the site is finished. Ongoing operation and maintenance is taking place at these spots and with these systems:

• The riverbank stabilization area along the Great Miami River.
• The constructed treatment wetland.
• Vapor well sampling.
• Horizontal soil vapor extraction system.
• Gulf Park Biovent system.
• The extensive groundwater sampling network. 

In November 2016, a 10-year Review Report was submitted to U.S. EPA to determine the current state of the cleanup. The Long Term Final Corrective Measures are what is called Monitored Natural Attenuation, which uses natural processes to degrade contaminants. 

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Site Description

The Former Chevron Refinery site dates to 1931 when Gulf Oil Co. produced gasoline, jet and diesel fuel, home-heating oil and sulfur. It was acquired by Chevron in 1985 and stopped operating in 1986.  Environmental investigations began in 1985 as a result of fuel seepage into the Great Miami River. In 1993 Chevron signed a legal agreement with U.S. EPA. The company started a "corrective action" investigation and cleanup with U.S. EPA oversight in 1993.  Investigations revealed a large area of polluted groundwater – called a plume – of floating hydrocarbons (mostly gasoline). Drinking water is supplied by the local water authority from clean sources in the next valley.   The hydrocarbons released lie beneath the facility 10-25 feet below the surface and extend west beneath the village of Hooven at 35-65 feet below ground.  Interim measures of 16 wells on the facility property have pumped out and treated more than 1 billion gallons of polluted groundwater and recovered 3.9 million gallons of hydrocarbon product since the initial pumps began operating in 1985.  In 2004, U.S. EPA approved a plan for Chevron to complete cleanup of polluted soil on the Chevron property trough excavation. The plan also included off-site disposal, and Chevron has carried out this plan.  In 2006, U.S. EPA finalized a legal order with Chevron to clean up groundwater that included addressing the vapor intrusion potential.  Vapor intrusion is the possibility of underground gases seeping into buildings and causing indoor air pollution. The potential vapor intrusion to nearby residences is dealt with by the horizontal vapor extraction system and monitored through vapor wells in the area. Fortunately, they have shown no vapor intrusion connection from the groundwater plume to residents living above the plume. 

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Contaminants at this Facility

During operation of the former Chevron Refinery from 1933 to 1986, an estimated 5 million gallons of refined product (gasoline and diesel fuel) was released into the aquifer under the site. Soil contamination consisted of Solid Waste Management Units and Areas of Concern, primarily from petroleum wastewater solids, which were excavated and hauled to off-site landfills. A total of 674,030 tons of soil had been removed when excavations were completed in April 2007.

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Institutional and Engineering Controls at this Facility

Engineering Controls:

The groundwater cleanup includes Monitored Natural Attenuation (MNA) as the long-term remedy, with the goal of meeting clean water standards called Maximum Contaminant Levels throughout the plume. The cleanup plan also

• comprises five year reviews of the remedy progress;
• a groundwater sampling plan;
• periodic high-grade groundwater pumping;
• a system to collect vapors from beneath the adjacent residential neighborhood;
• periodic monitoring of nested soil vapor wells; stabilization of the riverbank with a barrier wall to prevent the erosion of contaminated material into the Great Miami River; and
• contingency plans if performance measures are not met. 

Institutional Controls:

An Environmental Covenant (a type of institutional control) was finalized between U.S. EPA and Chevron in September 2016 that prohibits groundwater use, construction of basements, residential development (including reuses to sensitive populations such as daycare, assisted living etc.). It also specifies limits on utility trench excavation and ventilation requirements and requires vapor barriers be installed on slabs built over the groundwater plume.

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Land Reuse Information at this Facility

The Environmental Covenant in place anticipates potential commercial, industrial and passive recreational re-use. A corridor along the river has been turned into a natural habitat. 

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Site Responsibility at this Facility

Chevron is responsible for the site cleanup under the RCRA 3008(h) Administrative Order on Consent, signed November 2006, between U.S. EPA and Chevron.