Colorado oil and gas regulators on Monday began refining their rules for underground pipelines, spurred by a fatal house blast in Firestone in April and mindful that booming development driven by population growth is on a collision course with fossil fuels extraction. They propose requiring that companies to cut off old underground lines connected to oil and gas wells, test all active lines for pressure changes that could help detect leaks, and reveal more of the fires and explosions that happen along underground lines. But the Colorado Oil and Gas Conservation Commission members immediately faced flak from residents and local governments that their proposed refined rules, drafted by staffers, appears feeble. At the very least, a coalition of Front Range communities contends, state regulators must require companies to submit maps that could be made public showing locations of underground lines.