More Stories About Tanks – Part 2

Last month I outlined a couple of ESA case studies that explored some of the detailed historical research that can be necessary when investigating the potential presence or absence of underground storage tanks at a Site. This month I have a couple more stories to share that delve into the visual clues that may indicate the presence of USTs, along with the need for detailed interviews and other research items.

The City Mansion
I was recently asked to attend a site which contained a large mansion that was being sold. A home inspector had found a ‘Levelometer’ - a remote fuel gauge located in a garage outbuilding, and advised further investigation to determine whether a residential heating oil tank may be present. Sometimes it can be difficult to spot the clues, and find details about a possible tank, but at this Site all the hints, clues and data were there – if you knew where to look. The more I looked, the more interesting it got, for me anyway – the vendors were a bit surprised, but at least all stakeholders now had some definitive information to move forward.

• Visual inspection of the buildings encountered not one, but two Levelometer remote fuel gauges, and they both appeared to show fuel in their respective tanks.
• The second remote gauge was found in the basement boiler room, where concrete pads for an older boiler were also noted next to a newer multi-boiler heating system.
• Despite deep snow cover, we were able to locate one remote fill pipe on the exterior of the main house, and vent pipes in the exterior house and garage walls that were hidden behind decorative architectural features. The fill pipe for the garage tank could not be found due to heavy snow and landscape features.
• Lastly, a detailed review of the original 1960’s construction drawings (stored in the basement) provided details and exact locations for the original 2,000 gallon underground fuel oil tank supplying the (historical) house boiler; and the separate 500 gallon UST supplying the furnace in the garage outbuilding.

A subsequent geophysical scan confirmed both these USTs were still in place, and are now scheduled to be removed.

The Country Estate
The Site formerly contained a country estate home, which was developed from prior agricultural land for construction of a residential house in 1973. The house was demolished in 2011, in preparation for a proposed Site redevelopment. The local natural gas supplier reported that the Site had been serviced with natural gas since 2000 (the oldest records maintained by the utility). The natural gas service was reportedly disconnected in 2011 for the demolition. According to the current Site owner, prior to natural gas service, the residence was previously heated with a propane-fired furnace from 1987 to 2000. The previous and original site owners were identified through historical City Directories, and their current contact information was found online. The first owner (the widow of the original owner/builder) confirmed that the house was originally heated by an oil-fired furnace/boiler in the basement, but she could not recall the exact location of the oil tank. The next (second) owner reported that when he purchased the home, it was heated by furnace oil which was which was supplied by an exterior, underground fuel tank. It was a condition of his purchase that the 500 gallon UST and oil-fired furnace be removed, so that he could install a new propane fired furnace, which was later converted to natural gas when gas service was provided to the property in 2000. The second owner further reported that the UST was formerly located under the driveway in front of the attached garage, and was excavated and removed at the time of his purchase in 1987. A review of aerial photography, combined with the interview data, was able to pinpoint the former location of the UST for further investigation prior to initiating a Phase II ESA of the Site.

Sometimes, when it comes to exploring underground tanks you just need to dig a little deeper.

Bill Leedham, P. Geo., CESA
Bill is the Head Instructor and Course Developer for the Associated Environmental Site Assessors of Canada (www.aesac.ca); and the founder and President of Down 2 Earth Environmental Services Inc. You can contact Bill at info@down2earthenvironmental.ca