City officials considering whether to convert a closed Murray city landfill near 2000 West and 5000 South into a new park are dealing with two volatile byproducts: methane gas and potential public concern about that gas.
John I. Morgan, the city's administrative services director, said there is no immediate public health hazard from the methane gas, which was detected below the surface in the southeast corner of the 9.5-acre site."The methane is not a problem" at this point, Morgan said, "but we're talking with people and letting them know what's going on."
Mayor Janice Auger said Tuesday the city is still negotiating with Murray about possible purchase of the landfill site.
A study by Kleinfelder Inc., a local environmental research firm, found that the methane gas in the southeast sector was "seven times greater than the lower explosive limit for methane in air."
But Morgan said that gas is "vented naturally" at the present time through a thin cap of sandy material, dispersing into the atmosphere at non-threatening levels that do not pose a safety or health hazard to neighboring residents.
There could be a problem if the landfill were converted into a park with a lot of non-porous surfacing such as asphalt, he said, which would force heavier concentrations of the gas to migrate underground through the soil toward nearby residential areas.
Even then, Morgan said, there probably wouldn't be any danger unless a neighboring home had a crack in the basement wall.
But Kleinfelder has recommended that, if the city decides to go ahead and buy the property from Murray, a passive methane gas collector system should be installed to collect and safely disperse the gas. Methane is a natural byproduct from decomposed grass and yard trimmings buried beneath the landfill surface.
"It's really a fairly minor thing," Auger said.
The study was commissioned last summer after City Council members decided to find out whether the old landfill, closed by Murray city in late 1989 or early 1990, would make an acceptable park.
Other than the presence of methane, the study found few problems with the site.
Some petroleum-impregnated soil was detected on the east side of the landfill, but the study did not determine whether there is extensive oil contamination in that area.
What was found "should not present a health or environmental concern," the study said, "but may require some special handling" if the site is developed and the impregnated material is excavated.
There appears to be no groundwater contamination from the land-fill, and the waste buried there appears to be a relatively harmless mix of yard waste and construction debris, the study noted.
Bruce Wasden, City Council chairman, said the study is encouraging but noted the council is a long way from making any kind of decision about whether to purchase the landfill site.
"We're still very interested," he said. "But we are proceeding cautiously. We need to get into some serious discussion with Murray city and look at what it will take to mitigate the gas problems and what it will cost.
"We don't want to buy a pig in a poke," Wasden added.
Auger said about 200 people who live near the landfill site attended a public meeting late last year to discuss the proposed park.
"They were more concerned about what kind of park will be built" than the methane gas issue, the mayor said.
"Neighbors said they were more interested in having a park with open space" than athletic fields, she added, but Little League supporters are urging the construction of more ball diamonds.