Updated on 2/23/14 to correct the date of the 2013 CO measurements, and on 2/21/14 to add a data table from MDNR and more characterization of the recent CO measurements.
New monitoring data from the Bridgeton Landfill suggest that an underground fire has not spread toward radioactive waste to the north.
A map posted online by the landfill's owner, Republic Services, shows carbon monoxide levels below 1,000 parts per million throughout the north quarry. That's the part of the landfill closest to the radioactive material in the neighboring West Lake Landfill.
Carbon monoxide (CO) levels above 1,000 ppm would mean a flameless fire was smoldering underground (see p.7 of this report, excerpted here).
There's a caveat in celebrating these results. According to a table posted online by the Missouri Department of Natural Resources, the measurements were made on a single date: January 24. That means it's impossible to know whether the results represent the minimum or maximum concentration of CO for the month, or something in between.
According to a spokesperson for Republic Services, January's results are "very consistent" with previous CO measurements made in the north quarry in June 2013. [Correction: According to the Missouri Department of Natural Resources, the earlier samples were collected on July 22, 2013. You can see the results for yourself, here. The concentrations are shown in units of % v/v. To convert those values to ppm, you multiply by 10,000. For example, a carbon monoxide concentration of 0.0035% v/v is the same as a concentration of 35 ppm.]
The new data table also shows CO levels in what's known as the "neck" of the landfill ― the narrow stretch between the south quarry (where the underground fire began) and the north quarry (where the radioactive waste is stored). In seven of those wells, CO levels were above 1,000 ppm on at least one monthly sampling date since October. For six wells they were above 2,000 ppm, and for three wells, above 3,000 ppm. Again, since since CO was measured on a single date each month, those readings may ― or may not ― represent the monthly peak.
Ed Smith of the Missouri Coalition for the Environment said he's happy the state is getting more information about the fire. He was cautiously optimistic about the carbon monoxide readings from the north part of the landfill.
“We believe that vigilant monitoring is necessary,” Smith said. “And if the information's right, it's a little breath of fresh air in what is a very problematic situation.”
Last month, a court ordered Republic Services to do the additional monitoring, at Missouri Attorney General Chris Koster's request.
Koster had asked Republic Services to provide carbon monoxide data on a continuing, monthly basis. The Court set that matter for hearing in June. In the interim, Republic Services agreed to submit three sets of carbon monoxide data at 60-day intervals: in February, April and June.
In a written statement, a spokesperson for Koster's office said ongoing monitoring of carbon monoxide throughout the entire landfill “is critical to get the most accurate picture of the underground fire.”
But he said the AG would look to local first responders and the Missouri Department of Natural Resources to interpret the information.
The MDNR said only that it was reviewing the data and would post them on its website.
Some area residents fear what might happen if the underground fire reaches the radioactive waste. They are lobbying for the waste’s removal.
A spokesperson for Republic Services said the new data “will likely be very assuring to first responders, elected officials and neighbors” of the landfill.
Follow Veronique LaCapra on Twitter: @KWMUScience
