WELLS – Residents will be asked at their town meeting next month to approve a $4 million bond issue to purchase seven homes located over a landfill that has contaminated soil and groundwater.

Recent tests of soil, groundwater and air in homes near and on the landfill site revealed the presence of toxic gases and materials, some of which are known carcinogens.

The landfill, which was known as the Indian Trail Landfill, was built in the 1920s. When it closed in the 1970s, a layer of soil was put down to cover the site. A subdivision was built on and around the landfill.

Through the years, the town has monitored the site, and the Maine Department of Environmental Protection became involved in the 1990s. Testing eventually showed that the landfill was affecting wells.

In 2000 voters agreed to connect the neighborhood to town water.

The latest round of testing has found significant levels of polycyclic aromatic hydrocarbons in the soil around several homes. The chemicals, which are toxic if ingested, are formed from partially burned substances such as trash.

Tests also found levels of gases that are above U.S. Environmental Protection Agency guidelines in soils. The gases included benzene, which is a carcinogen, and methane, which is flammable.

None of the gases were found in people’s homes, and no resident has reported ill effects. But officials are concerned that these gases and chemicals could build up over time and cause health risks.

While it does not seem that any resident is in immediate danger from the landfill, town officials decided the best solution would be to buy residents’ homes and move them away from the site.

Paying to move residents is considered the most conservative way to guard against health risks, but town officials said their decision also is the best way to bring residents peace of mind.

“Our gut feeling is, most people want to move,” said Town Manager Jon Carter. Other steps to be taken include installing ventilation systems to help release the gases from the soil.