A simple asbestos abatement project at the Hudson Oil Refinery in Cushing, Oklahoma evolved into one of the most interesting, complex and dangerous projects that contractor CET Environmental Services Inc. has ever managed.

On August 11, 1998, Englewood, Colorado-based CET was awarded a delivery order under an indefinite delivery/indefinite quantity (IDIQ) contract by the US EPA to oversee the removal of asbestos-containing materials from the southern side of the former oil refinery. However, on the northern side of the 250-acre site, the team investigated an alkylation plant. (Also known as a “cracker unit,” the plant is used to break down crude oils into other marketable petroleum distillates such as gasolines, diesels and light-ends.) A small leak in a pressure vessel was detected and a tank was discovered that contained more than 6,000 gallons of 99 per cent-pure anhydrous hydrofluoric acid! The ancillary pipe valve integrity was very poor.

Hydrofluoric acid boils at 19.4¡C (67¡F) and is four times more toxic than cyanide. Though the effects of the chemical are not immediate, they’re deadly. An exposed person will feel the effects anywhere from 8 hours to three days later; the acid moves through the body systemically and removes calcium from the blood, which ultimately leads to heart failure. A mere splash on a person’s hand can be lethal. Inhalation of the vapor can dissolve lungs. It even changes bone composition to calcium fluoride, turning bones to jelly.

The EPA estimated that the vapor plume produced by a spill as small as just 20-gallons would have covered the area and could have killed many of Cushing’s 6,000 residents.

Acid and contamination response

The $5-million-plus project required two response managers. One handled the hydrofluoric acid transfer as well as the alkylation plant decontamination and demolition. The other managed the asbestos abatement, the removal of sludge and petroleum liquids from tanks and drums, and the decontamination and dismantling of containment structures.

At least one month was spent evaluating and developing the scope of work and safety protocols. Handling methods that were examined included “cooking off” the acid by raising the boiling point above 19.4¡C (67¡F) and slowly venting the material away from residential areas. Another method included displacing the acid from the tank with nitrogen to a transportable vessel and directing the displaced vapor to a carbon scrubber and then to a lime tank (pH 13) to neutralize the purged acid and petroleum vapor. Experts were consulted, including the EPA, the Washington, DC-based Hydrofluoric Acid Institute and Newark, New Jersey-based Allied Signal (the largest manufacturer of hydrofluoric acid).

The initial mobilization of the environmental team to Hudson Oil occurred in October 1998. An additional forty CET employees were mobilized; people who were familiar with the site and were well prepared to respond to an emergency. Everyone participated in meticulous practice runs and numerous safety meetings.

Evacuation of Cushing residents took place on December 14, 1998. A total of 435 people were evacuated from a 1/3-mile area to allow for the transfer of more than 6,000 gallons of hydrofluoric acid to a holding tank.

The next phase of the plan consisted of “hot tapping” (accessing lines under pressure) and “inerting” (displacing one gas with another) approximately 3.5 miles of refinery pipeline and more than 90 vessels that contained the highly flammable, corrosive and poisonous mixture of hydrofluoric acid and petroleum gases. In this case, heated nitrogen was used to displace the acid and petroleum gases from the pipeline. This process was completed in August of this year.

Since hydrofluoric acid is so deadly, CET set up a virtually unprecedented 19-point decontamination system. The EPA’s onsite coordinator Rita Engblom says, “I’ve never seen decontamination activities that complex, even in HazWOPER training courses.”

Other contaminants

At other areas of the site, drums and other contaminant-bearing containers were segregated and then further separated according to waste stream and “Hazcatted.” (Hazcatting [or categorizing] is performed on unmarked drums and/or containers. It’s an empirical field analysis of the unknown substance that measures basic chemical properties and constituents.) Once similar materials are Hazcatted, representative volumes are typically consolidated based on end disposal requirements, sampled to determine specific constituent concentrations for respective transportation and disposal characteristics, and packaged for Ô transportation and recycling or disposal.

Again, although the environmental contractor was initially hired for asbestos abatement, it found that the refinery tanks and pipes had not been purged. Refinery product had corroded pipelines for more than a dozen years and caused systems to fail. Before demolition could occur, the pipelines and tanks had to be purged of various petroleum hydrocarbon products.

The asbestos abatement continues on the southern side of the refinery by subcontractors. The site will soon be given a National Priorities List ranking which will lead to a remedial investigation and feasibility study. Funds from the US Department of Transportation, legislated by the Oil Pollution Act, 1990, will be used to address soil contamination onsite (probably with bioremediation).

Health & safety

The EPA has noted the cleanup operation’s excellent health and safety record. With more than 15,000 hours in the project there have been no “lost-time” accidents. This is outstanding when one considers the dangers associated with the long hours and the multiple pieces of equipment, including cranes, bulldozers and backhoes. All are synchronized to perform quickly and safely.

Assistant Zone Program Manager Ron McManamy says, “This project is one of the most complex and multifaceted sites that CET has managed. CET’s development and coordination of operational and safety aspects with the city and the residents of Cushing as well as the various state and federal authorities required significant time and effort to make the evacuation and transfer a success.”

Once all cleanup activities are completed, and all legal claims by Payne County, the State of Oklahoma, the EPA and other affected parties are settled, an effort will be made by the City of Cushing to attract other manufacturing and/or light industrial businesses to the remediated site.

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