During initial testing, methane levels of 29% and 35% were consistently detected in several test wells located under the footprint of the proposed stadium.  Methane reaches explosive levels in the air at concentrations of 5-15%.  RMT, the consulting firm initially hired to investigate the methane problem, identified two sources of the gas - old landfilled garbage and what appeared to be marsh gases generated by organic silts laying further below the trash.

In 1952, the builders of old County Stadium first discovered the existence of methane gas at the site.  An engineer smoking a cigar near one of the soil bore holes ignited the gas, blowing the eyebrows off his face.

The addition of a roof to Miller Park has made the matter of methane buildup more pressing.  RMT called the excavation and removal of all the methane generating materials "impractical."  Removal of even the 5-20 feet of trashy debris (the depth varies across the site) could worsen the marsh methane problem by reducing the soil cover, according to a report prepared by an analyst working for Milwaukee County’s Board of Supervisors.

The Stadium Board chose to hire a second consultant to help with their methane problem.  The new consultant offered a different perspective.  Their answer, according to Stadium Construction Manager Ken Kazabowski, "is a very cost-effective solution."

The construction contractors scrapped off about eight feet of trash, installed a barrier wall around the stadium, and then placed a passive venting system in the ground, consisting of pea gravel with perforated piping.  "I would call it elegant," Kazabowski says of the approach which cost slightly less than $1 million.

The DNR’s Bizhan Sheikloleslami indicates that by removing the trash, "they took care of, in our mind, the problem that was below the building."  Sheikloleslami says that the DNR wasn’t politically pressured to make the stadium site work, although he notes that the Department of Transportation and Division of Administration have been the lead state agencies involved with the project.

At a different methane generating site in Milwaukee, the DNR demanded a more elaborate and expensive solution.  The city’s Florida Yards site needed concrete packing and special footing and foundation standards for the building along with the perforated piping, gravel, and barrier membrane.

The DNR is requiring placement of a methane detection and alarm system under the new stadium.  The equipment won’t be operational until the stadium’s construction is finished.

All parties associated with the methane removal plan believe it’s going to work, but, as Kazabowski says, "you never know with 100% confidence that what you’re doing is right."