BART is spending hundreds of thousands of rider dollars on an extraordinary legal challenge of the state Public Utilities Commission’s authority to punish the transit agency for breaking its own safety rules in the deaths of two track workers back in 2013, NBC Bay Area’s investigative unit has learned.

The unusual war over regulatory oversight authority – which records show has cost $850,000 to date -- rankles at least one member of BART’s elected governing board.

“I can’t really comment on the case itself, but in my opinion, BART cannot effectively regulate itself on anything, and history has proven that," BART board member Debora Allen said.

After years of regulatory hearings, the state utilities commission approved a $1.3 million fine this year, alleging a total of seven safety violations in the 2013 deaths of two workers struck by an untrained operator learning to fill in during a strike.

Recently, as part of its terms of probation for seven safety violations, BART began to post compliance notices at its stations. The notices mention the fine, and that it could be cut in half if it fulfills conditions of its probation, but make no mention of regulators' findings related to the deaths of the workers, Christopher Sheppard and Laurence Daniels, or the fact that BART has lodged an appeal that alleges that the state’s Public Utilities Commission is abusing its regulatory authority.

The state’s regulatory case is based in part on a video from inside the cab that day, Oct. 19, 2013. The video shows the untrained driver appear to panic as he struggles, alone in the cab, to sound the alarm to alert the two track workers up ahead in Walnut Creek.

It also shows how the designated trainer, Paul Liston, grumbled about having to get up to help the fledgling stand-in operator in the minutes before the accident.

One of the regulatory violations grows out of BART’s rule that the trainer must directly oversee the trainee, given that the video reveals that Liston – who has since retired – was in the passenger compartment when the accident occurred.

In its argument, BART claims that citation and four other violations are legally invalid, as they involve its own rules. The law doesn’t allow the commission to punish over BART rulebreaking. And the five violations constitute “an unlawful expansion of the commission’s authority over a statutory public agency.”

BART argues that the commission can only enforce its own rules, not BART’s.

In a response brief filed last month, regulators counter that BART’s argument “defies both logic and law” and could leave the agency hamstrung in holding BART accountable for safety lapses.

No matter who is right, records show that as of now, BART’s legal tab is $850,000 waging the war against regulators. BART says the sum already accounts for all the costs of the as-yet unheard appeal.

But that tab already exceeds the $680,000 BART would have to pay by simply following the terms of its three-year probation.

BART board President Bevan Dufty now says he will ask for a closed-door legal briefing before the full BART board after learning about BART’s appellate fight with regulators from NBC Bay Area.

In a statement, BART said the fight “concerns several very important issues” over the proper use of evidence and questions about due process – as well as legitimate questions about the boundaries of the commissions lawful regulatory authority.

Still, BART boardmember Allen says there’s value in having an outside agency charged with protecting public safety, “Third party oversight is necessary at BART,” adding, “More is better.”