Milwaukee, Wis. ? More than 130 wind turbines are proposed for the hilltops of central Wisconsin, but that project and at least 11 others have been halted by the Defense Department as it studies whether the projects could interfere with military radar.

Wind farm developers, Midwestern legislators and environmentalists say the farms pose no risk, noting that there are already numerous wind farms operating in military radar areas. They say a renewable, domestic source of energy such as wind is crucial to energy security and independence.

This spring, facilities in the works in North Dakota, South Dakota, Illinois and Wisconsin received “proposed hazard” letters from the Federal Aviation Administration saying the projects must be halted pending the Defense Department study.