DENVER (AP) — Backers of two proposed ballot measures to change how oil and gas drilling is regulated failed to get enough signatures to get them on this fall's ballot, Colorado Secretary of State Wayne Williams said Monday. Both were opposed by the energy industry and by Democratic Gov. John Hickenlooper, whose administration has insisted on state regulation of the industry. Combined with other drilling techniques, it opened up previously inaccessible oil and gas reserves and boosted the economy, although low oil prices have led to widespread layoffs and a steep decline in drilling. The proximity of oil and gas development to residential neighborhoods also is a contentious issue in Colorado.