Underground Storage Tanks
I. The Issue:
Experience has shown that the filling and use of underground tanks for the storage of hazardous materials such as petroleum may result in the accidental release of the stored material. In addition, a number of studies have found that approximately 50% of all underground storage systems begin to degrade and fail within fifteen years after installation. Furthermore, tanks with a smaller volume and constructed of a lower gauge or thickness of steel tend to fail sooner than larger thicker tanks. The release of hazardous materials by these tanks may adversely impact the local environment by contaminating local soils, groundwater, and surface water. These impacts may create public health issues while also establishing state and federal regulatory responsibility and liability for the tank owner. As the owner and operator of underground storage tanks, it is imperative that we properly monitor and manage these systems to prevent the release of hazardous materials so that we can protect the health of the local citizenry and environment, and avoid unnecessary regulatory costs.
II. The Approach Taken:
In 1992, we began our effort by reviewing local records to determine if underground heating oil tanks were present at any of the local schools. We reviewed construction plans, tank installation and removal records, and consulted with school department personnel.
In 1995, the School Department investigated and removed its first underground storage tank during the renovation of a local elementary school.
In 1997, in response to the discovery of a number of leaking municipal underground storage tanks, the Town of Burlington initiated steps to investigate and remove all aging tanks owned or operated by the Town.
In June 1998, the Town of Burlington began efforts to investigate and remove six underground storage tanks from four local schools.
III. Observations Made:
As a result of this investigation, we found that at least one underground storage tank was present at each local school. The size of the tanks ranged from 500 to 20,000 gallons in capacity. The ages of the tanks ranged from 20 to 40 years of age. At several locations, we also noted that available records suggested that only one tank was present on site, but that the piping at the school suggested the presence of more than one tank. We also noted that many of the school department tanks had been abandoned in place after the department had converted the school heating systems to natural gas. In many cases the tanks were found to have been left in place unused for years. In addition, recent tank removal activities have determined that approximately 30,000 gallons of oil was left in place when these tanks were originally abandoned. One tank was found to contain approximately 18,000 gallons of aged fuel oil. These practices represent multiple violations of state and federal underground storage tank requirements. In general terms, all underground storage tanks in Massachusetts must be excavated and removed within two years of abandonment. As part of the removal process, a tank closure assessment must be completed to determine if environmental contamination has occurred. Also, the contents of each tank must be removed at the time when the tank is taken out of active service.
Between 1995 and 1997, we removed three underground storage tanks from school property. During this effort, we removed a 500 gallon tank (which was found to contain 500 gallons of diesel fuel at the time of removal), a 5000 gallon tank (which was found to contain 3000 gallons of heating oil at the time of removal), and an 8000 gallon tank. Contamination was discovered at two of these locations. The discovery of contamination triggered the Massachusetts environmental reporting requirements which then mandated that the town remediate these petroleum releases.
During the summer 1998, we will be attempting to remove at least six more tanks. Many of these tanks have been found to have residual oil in place. It is likely that we will detect additional contamination before this project is completed.
IV. The Problems or Concerns Noted:
- Local tank records are poor. Many inaccuracies have been noted with regard to the number, size, location, and use of the tanks.
- Most of the tanks are more than 25 years old, which increases the risk of tank failure and a release of hazardous materials.
- Several tanks are located within environmentally sensitive areas.
- No tanks were removed when the school department converted their heating systems to natural gas.
- Thousands of gallons of fuel have been found to be abandoned in place with the tanks when the energy conversion occurred.
- Past tank management practices represent multiple violations of state and federal tank management requirements.
V. Actions Taken:
To the best of our ability, we have identified the number and location of tanks believed to be present at local schools. So far we have removed three underground storage tanks from school property. The two sites which were found to be contaminated have been remediated and resolved. In the summer of 1998, we plan to remove six underground storage tanks from four local schools. We anticipate that this effort will also involve additional release abatement measures.
1. Local tanks records are often inaccurate or incomplete. We found many discrepancies when comparing written information with on site piping and structures. Be sure to conduct a comprehensive evaluation prior to initiating tank removal activities. Also, be prepared to respond to the discovery of 'new' previously unknown tanks.
2. Remove the contents from all tanks prior to abandonment. Failure to remove the contents prior to abandonment can allow the tank to become a perpetual source of contamination should it leak. In addition, this is a waste of money because you have paid once to obtain the heating oil for heating purposes and you will pay again to dispose of this material as a hazardous waste when you remove the tank.
3. Be sure to review the records and seek verification. Our effort was seriously delayed because several key individuals decided to accept statements reporting that all the tanks had been removed without consulting existing documentation or reviewing site conditions. Be diligent and thorough so that you can avoid a very costly problem.
Tips and Suggestions:
1. Always check the contents of your tanks before initiating removal actions. Preplanning can make the budgeting and removal process easier. This can also help you prioritize your efforts.
2. If your tank is found to contain materials, then have the contents removed to eliminate the potential for additional materials to be released from the tank.
3. Learn and familiarize yourself with state and local tank regulations as well as sensitive environmental receptors in your area.
4. Establish a system to monitor and upgrade/remove your aging tanks as a means to prevent a costly release.
Prior to initiating a tank removal effort, I recommend that you seek the advice and assistance of your local fire department as well as state and federal environmental agencies. They can inform you about local regulatory requirements as well as the availability of grants designed to assist these efforts.
prepared by Todd H. Dresser, Environmental Engineer
Burlington Board of Health, 29 Center Street, Burlington, MA 01803