Bill Olson escaped the purge, thanks to his impending retirement. One of his biggest accomplishments, however, quickly came under fire. As chief of the groundwater bureau, Olson led a team that spent two years crafting the nation's strongest rules for mega-dairies, which are serious polluters in California, Washington and Idaho, as well as New Mexico. It required monitoring wells to quickly detect leaks, and synthetic liners to keep nitrates, and salts, from seeping into groundwater from manure lagoons. The dairies boycotted the rule's initial advisory group process, balking at the regulatory expense and oversight, and threatening to take their 4,000 jobs elsewhere. Nevertheless, the Water Quality Control Commission approved the rule at the end of Gov. Bill Richardson's term.

The dairy rule came on the heels of a similar Richardson-era rule for oil and gas producers that encouraged closed-loop systems instead of open waste pits. It, too, was one of the nation's strictest. The state's groundwater protections looked stronger than ever.

That began to unravel under Martinez, beginning with her executive order halting new regulations, including pioneering greenhouse gas regulations as well as the dairy rule. (Dairy lobbyists, it was later revealed, helped draft that order.) After the New Mexico Environmental Law Center successfully sued, and the dairy rule went on the books, the industry appealed. By October 2011, Olson had negotiated a new rule for the state, and retired. But he testified for free at the final hearing, where the commission passed a compromise rule that left everyone modestly satisfied.

For the Martinez administration, the success was partial: The rule was revised rather than killed outright. The copper rule, however -- the development of which was, like the dairy rule, legally mandated -- would be written entirely on its watch, presenting a prime opportunity to reshape groundwater policy.

Southwestern New Mexico has been a copper-mining hub for more than 100 years, and the state is currently the nation's third-largest producer. Freeport McMoRan, the world's second-largest copper company, owns the Chino, Tyrone and Cobre mines, and employs about 1,600 people in the sparsely populated area around Silver City.

The consequences of failed pollution prevention are already evident at the three mines. Groundwater beneath about 20,000 acres is contaminated with sulfuric acid, sulfates and heavy metals that have seeped into it from leach piles, unlined tailings impoundments, and waste-rock heaps. Domestic wells aren't affected, but studies estimate that contamination could enter their water sources in 40 to 50 years, should Freeport McMoRan stop pumping water from the Tyrone Mine.

In January 2012, two Environment Department managers who have since left asked Olson if he'd like to consult on a rule to prevent further pollution. Olson agreed, and spent nine months leading an advisory group of agency staffers, copper industry reps, environmentalists and concerned citizens through the regulatory weeds as they hashed out a draft.