Yellow tubes snake from the top of converted landfill vents, running underground for a few hundred feet before leading back above ground to a flame fed by a steady supply of methane gas.

The system is designed to protect the nearby library, civic buildings and neighborhoods from the potentially explosive gas, constantly seeping from decomposing waste underneath the soil at the closed Kentwood Landfill.

Prompted by detection of methane migrating outside the perimeter of the facility last year, work began in August to expand methane collection, containment and monitoring at the site. Methane, which occurs naturally in landfills, is non-toxic and dissipates quickly when exposed to air. But the gas is flammable, specifically when trapped in closed-in spaces.