The Department of Environment and Natural Resources (DENR) has provided an update of the gas spill at occurred Rubis facility in Ferry Reach on March 27.
Liquid gasoline product has not been detected at three of the new wells and a slight sheen was detected at one new well to the south-west of the spill location. Furthermore neither liquid product nor vapour product has been detected at the two private wells to the south of Ferry Reach Road. These private wells will continue to be monitored by RUBIS at a rate of two to three times each day. The Department has contacted neighbours to the south to let them know if they were to smell any chemical fumes to notify the Department immediately.
RUBIS will continue to monitor these wells surrounding the spill and will consider putting additional wells in to fill in the missing areas and if the liquid product spreads then this will necessitate the drilling of new wells to ensure that the full extent of the liquid spill is always understood.
RUBIS has already made a start to remove the gasoline from the ground from an existing small-diameter monitoring well using a vacuum truck. Additional specialists are en-route to Bermuda to drill larger-diameter recovery wells in the centre of the spill that will provide a greater recovery rate of the gasoline once additional equipment has arrived.
Additional equipment to address the vapour plume using soil vapour extraction is also being set up. The recovery of the liquid product will be followed by recovery of the vapour phase of the gasoline and the monitoring will continue (i.e. liquid product thickness, well headspace, and dissolved constituents in the groundwater) to the standards that are set in Bermuda’s Risk Based Corrective Action (RBCA) Guidelines. Under these guidelines the recovered product and associated water must be properly disposed of at the Government Hazardous Waste Facility or via other approved methods.
For information the estimated 73,000 litres (i.e. 19,300 US Gallons) of gasoline liquid percolated down through approximately 14 metres (i.e. 45 feet) of limestone before reaching the groundwater where it was expected to float as a lens on top of the groundwater and spread out laterally. In addition to the liquid gasoline floating on the water table and spreading out laterally the fumes from the gasoline are also expected to spread out in the porous limestone above the liquid plume and water table. These fumes are referred to as the vapour plume and this is expected to travel ahead of the liquid gasline plume.
In summary, the Department of Environment and Natural Resources considers that the full extent of the liquid gasoline plume that is floating on the groundwater is understood and is contained fully on the RUBIS site. However, the vapour plume of fumes above the water table has extended to the four recently drilled wells with one of the wells also exhibiting a slight sheen. The recovery of the liquid product has started and will increase once further specialist equipment and personnel arrive on site.
The Department requires daily report logs of the monitoring of all appropriate wells on the Rubis site in addition to the wells located off the Rubis site. Weekly reports of the monitoring data, status of the liquid and vapour plumes in addition to data on the recovery of the liquid product are being provided according to established procedures in Bermuda.