At a hearing this morning, Colorado regulators will consider a new rule that would force oil and gas companies to disclose what chemicals they use when hydraulically fracturing wells. The industry uses these chemicals along with a mix of water and sand to “frack” wells deep beneath the earth. Nearby states like Wyoming and Texas recently put similar “mandatory disclosure” laws on the books and many oil and gas companies have recently come on board with Colorado's proposal. But some say the rule doesn’t go far enough.