By FINN BULLERS
The Kansas City Star
July 8, 2006

A year ago, the nasty smell of rotten eggs fouled the air for thousands of residents living near an Overland Park landfill. But efforts to stanch the stink are beginning to pay off. Hydrogen sulfide, the poisonous gas responsible for the odor, has not been detected since March 8 at the perimeter of the APAC/Reno site, said geologist Phil Askey, a Johnson County environmental compliance officer.

The landfill, at 167th Street and U.S. 69, handles construction debris. It is the largest of its kind in Kansas. Tests of nearby wells conducted in April and May show that contaminated water is not leaving the site and migrating to underground water supplies, Askey said. A second round of testing will be conducted this summer to confirm those results.

Federal investigators recently placed air quality monitors in five undisclosed locations in neighborhoods east of the landfill, businesses to the west, and schools and a church to the northeast. Investigators will start collecting samples to identify whether hydrogen sulfide emissions have reached critical levels, said Denise Jordan-Izaguirre, a Kansas City-based toxic substances investigator with the federal Centers for Disease Control and Prevention. “We want to make sure there isn’t anything out there that would harm anyone for even a day,” she said.

The smell of rotten eggs began bothering neighbors last summer when unusually heavy rain mixed with landfill runoff from an on-site asphalt plant percolated through the construction debris — wood, drywall and concrete — releasing hydrogen sulfide. Residents complained loudly, and state officials called in toxic substance investigators to determine whether gas emissions in nearby neighborhoods had reached harmful levels. Several months went by, however, before the monitors were installed while investigators concluded work in the aftermath of Hurricane Katrina.

Meanwhile, two holding tanks have been added to treat landfill seepage before it enters retaining ponds, said officials at the landfill’s parent firm, Ashland Pavement and Construction of Atlanta. Methane gas produced by the construction waste also is being captured to fuel the asphalt plant. And experiments to contain possible contamination are continuing.

Landfill owners await a state ruling on whether they can continue to operate the permitted 50-acre site on what has now grown to 82 acres.

Millions of gallons of toxic stew still sit in holding ponds at the landfill. The stink problem was a first for Kansas and a puzzler for the landfill industry, which has rarely seen such a toxic gas buildup.

The federal testing is being done by the Agency for Toxic Substances and Disease Registry, which is part of CDC. Readings will be compared with those collected by county and state officials and with other toxic sites across the country, Jordan-Izaguirre said.  Those readings will then be adjusted for weather conditions like wind patterns and vulnerable populations like day care operations and schools. Data will be collected for one to two months. “People need to know, yes, we’re out here. But don’t be surprised if it’s late winter or early spring before we have definitive results,” Jordan-Izaguirre said.

All results must first be reviewed by peer investigators outside her agency. Regulators will intervene sooner if sustained hydrogen sulfide readings reach a level of concern, she said.  “There’s nothing about hydrogen sulfide that is good for us,” Jordan-Izaguirre said. “So if you don’t hear anything for months, that’s good news.”