On April 20, 2015, the Colorado Supreme Court released an important decision restricting the use of so-called "Lone Pine" orders. See Antero Resources Corp. v. Strudley. Lone Pine orders require plaintiffs in toxic tort cases to provide evidence sufficient to establish a prima facie case of injury, exposure, and causation, before discovery has opened or face dismissal of their claims. The orders are named after an unpublished decision from New Jersey, Lore v. Lone Pine Corp. While Lone Pine orders are permitted under the Federal Rules, the Antero decision holds that such orders are not permitted under the Colorado Rules of Civil Procedure and will impact all toxic exposure cases in Colorado.

The Strudleys sued Antero and others alleging injuries caused by the defendants' natural gas drilling operations near their home. They alleged that pollutants from a drilling site contaminated the air, water, and ground near their home, causing them to suffer burning eyes and throats, rashes, headaches, nausea, coughing, and bloody noses. Causation was immediately at issue. After the parties exchanged initial disclosures, but before discovery had commenced, Antero moved for a modified case management order that would require the Strudleys to present prima facie evidence to support their claims before discovery could continue. The trial court granted the motion and issued a Lone Pine order directing the Strudleys to provide evidence to support their allegations of exposure, injury, and causation before the court would allow full discovery.

In response to the Lone Pine order the Strudleys provided some expert evidence and water test results, among other things. The Strudleys did not, however, provide an expert opinion concluding that they had been exposed to dangerous chemicals or that Antero's conduct had caused their injuries. Antero moved to dismiss asserting that the Strudleys failed to comply with the modified case management order and the trial court dismissed the case.

The Strudley's appealed and the Colorado Court of Appeals reversed the trial court. The Supreme Court affirmed the Court of Appeals. The Supreme Court recognized that trial courts have discretion to control discovery, but the Court noted that The Colorado Rules of Civil Procedure differed in significant respects from the Federal Rules of Civil Procedure upon which "Lone Pine" orders have been fashioned. Colorado Rule of Civil Procedure 16 does not expressly allow trial courts to fashion detailed case management orders like the Federal counterpart. The Colorado Supreme Court reasoned that "if a Lone Pine order cuts off or severely limits the litigant's right to discovery, the order closely resembles summary judgment, albeit without the safeguards supplied by the [Colorado] Rules of Civil Procedure." Thus, the Court held that because no statute, rule or prior Colorado case authorized the trial court to enter a Lone Pine order in a case involving just a single family, the trial court had erred in dismissing the Strudley's case.