The biggest change came in February when regulators changed how flowlines are created, tested and eventually abandoned.
Colorado Oil and Gas Conservation Commission
CPR News found a common practice designed to let oil and gas companies maintain ownership of old holdings.
Energy producers are responding to prices.
The regulations set requirements for installing, testing and shutting down flowlines, which carry oil and gas from wells to nearby equipment.
The plaintiffs want state regulators to require energy companies to show they would not harm human health or the environment before drilling.
Drilling activity doubled as the price of oil jumped last year. Along with that, there were 88 more spills of oil or water from drilling sites.
Few, if any states, map flowlines. Big energy developing states like neighboring Wyoming or Texas do not have any mapping requirement.
Colorado regulators will discuss what, if any, revisions are needed to the rules. They could approve them as soon as today.
Broomfield City Council is expected to vote on a long-awaited drilling agreement with Extraction Oil & Gas later this month.