Construction Moves Forward on Ronald McDonald House Expansion
Division of Environmental Response and Remediation Finds Remedy for Soil Contamination at Building Site
Earlier this year, it looked like the "the house that love built" would have to put its expansion plans on hold after contractors for Ronald McDonald House Charities (RMHC) discovered gasoline contamination on property slated to house their new 38,000 square foot facility. The Division of Environmental Response and Remediation (DERR) assisted RMHC by facilitating the installation of a vapor barrier so construction could proceed.
A Tradition of Caring
"For families across the Intermountain West, the Ronald McDonald House is a place to call home when a child is seriously ill or injured, "explained Carrie Romano, Executive Director of RMHC of the Intermountain Area. Since it opened its Salt Lake facilities in 1988, RMHC has provided thousands of families with comfortable, affordable accommodations and a supportive environment while a child is in the hospital or receiving extensive medical care. Demand, however, has outstripped RMHC's resources. "Last year, we had to turn away 588 families because we did not have the rooms to accommodate them," stated Romano.
Ronald McDonald House Charities developed a long-term plan to almost triple the number and variety of rooms available to families and create healing gathering spaces for patients and their families. RMHC decided to purchase property adjacent to their current facility on South Temple Street in Salt Lake City to expand their campus to serve 46 additional families.
In 2005, RMHC purchased the Sinclair gas station located next to their current building. Older underground storage tanks (USTs), such as those found under the Sinclair station, were used to store gasoline and diesel and had the potential to leak into the soil and groundwater. Soil and groundwater samples often show low levels of gasoline contamination at gas stations, but these sites do not always require additional remediation if the contamination poses no current or future threat to human health. To account for this possibility, RMHC leased the station back to the station operator under the condition that he remediate the site at the conclusion of his lease.
Although the operator agreed to this remediation, he left town before his lease expired. RMHC then became responsible for the tank removal and remediation of any contaminants found on the property. RMHC hired environmental contractors to remove the station and underground storage tanks and perform site remediation. Certified soil and groundwater samplers working for the environmental contractors took soil samples of the site. DERR inspected the site and issued "no further action" (NFA) notices based on the soil sampling and assessment of the soil and groundwater pathways for contaminants on the site. Following receipt of these NFAs, RMHC obtained the necessary funding and clearances to begin construction of its new facilities.
While excavating for a footing for one of the walls, contractors unearthed an old residential oil tank and found contaminated soil located more than 20 feet below the ground level. The residential oil tank had probably provided oil for the houses that occupied the property around the turn of the twentieth century. Although the tank was empty, contractors found soil containing high levels of gasoline contamination at this location. Apparently, gasoline from one of the excavated UST systems had leaked and traveled along piping trenches and fill material to the oil tank and collected there. Because the oil tank was located at a greater depth than the shallow lines of the known UST systems, it had escaped earlier detection.
Sampling of the deeper soil in the location of the old oil tank showed the surrounding soils tested high for benzene. The benzene levels found around the heating oil tank were higher than would typically be found near an old heating oil tank. It was determined that the benzene was from the former gasoline UST system.
While benzene evaporates quickly when exposed to air, it breaks down more slowly in soils and water. Exposure to benzene can cause serious health effects, particularly for sensitive populations.
Construction stopped. RMHC still had to pay the contractors for every day they were idle. Total site remediation to remove all possible benzene on the property would be impractical and prohibitively expensive. RMHC came close to abandoning the project as costs mounted and a solution seemed nowhere in sight.
Vapor Barrier a Win-Win Solution
RMHC approached the environmental scientists in the Underground Storage Tank Branch in DERR for assistance. The Leaking Underground Storage Tank program (LUST) of DERR oversees remediation of contamination from USTs.
"LUST scientists and engineers review and establish cleanup guidelines, define the degree of hazard, and take action to abate the hazard and remediate the site," explained Brent Everett, director of the Division of Environmental Response and Remediation. "Responsible parties such as RMHC seek the guidance of the LUST staff to ensure cleanup in a timely and economical manner."
The environmental scientists from the LUST program also determined that some of the remediation efforts at the RMHC site could be funded by the Petroleum Storage Tank (PST) fund. The PST fund is a trust fund administered by the DERR. Many gas station owners use the fund to help pay for eligible environmental cleanup costs.
DERR scientists and RMHCs consultant, IHI, determined that it would not be feasible to remediate the entire property to the depth of the contamination and keep the RMHC expansion on a reasonable timetable. The majority of the contamination is located outside the building footprint, where bacteria in the soil breaks down the contamination so it can degrade naturally until it is no longer considered a threat to human health or the environment. Unfortunately, it can take many years for the bacteria to break down these contaminants.
RMHC removed the contaminated soils around the tank and backfilled with clean soil. The extent of the benzene contamination underneath the building footprint was unknown. Placing a facility on top of potentially contaminated soils could lead to benzene vapor intrusion into the building, since vapors trapped below the building could eventually migrate to the surface and enter into the housing through the foundation. What RMHC needed was a way to protect the residents in the new facility, particularly sensitive populations, from vapor intrusion from the underlying soils.
The solution was to install a vapor barrier and passive venting system in the foundation of the new building. Since this type of ventilation system is most effective when integrated into new construction, the timing was ideal.
Contractors used strips of plastic vapor conduit to direct the vapors to specific venting points. The vapor barrier installation took place in stages over several days:
- Workers laid the conduit in a crosshatch pattern inside the footprint of the building, covered it with sand and a liner, and sealed it with asphalt material.
- The conduit connected to a venting pipe that runs through the outside walls of the building and vents any vapors out through the roof.
- Workers conducted several "smoke tests" to detect any leaks in the liner before placing an additional liner and sand on top of the first liner.
- Workers poured concrete over these layered liners, and proceeded to lay the floor of the foundation.
After the RMHC contractor installed the vapor barrier, construction continued as planned. "We were thrilled and relieved," exclaimed Romano.
Construction on the new facility is proceeding smoothly. RMHC will conduct periodic indoor air testing and water monitoring at the site to protect the health and safety of the residents of the Ronald McDonald House and the surrounding neighborhood.
"The Board and staff are grateful that the planned housing expansion is moving forward. Further delays would have meant fewer families could access the critical housing RMHC provides," said Romano. "We can't thank the staff at DERR enough for their help and support."
"We are happy we could find a solution that ensures that the facility and its surroundings are environmentally safe for the families housed there," added Everett, " so the "house that love built" can continue to serve families in need."