DENVER (AP) — Colorado oil and gas regulators voted Tuesday to expand the mandatory buffer zone between new wells and school property, a rare victory for proponents of tighter rules for the industry.

The state Oil and Gas Conservation Commission will now require that new wells be at least 1,000 feet (305 meters) from any outdoor area or building used by schools and day care centers.

The old rules required the same size buffer zone but measured it only from buildings, not outdoor areas. That allowed wells to be drilled closer to playgrounds and sports fields.

The rule also applies to future fac...