This photo provided by the Minnesota Department of Health shows vials of the injectable steroid product made by New England Compounding Center implicated in a fungal meningitis outbreak. (Associated Press)

If you want understand what went wrong with the pharmacy in Massachusetts, whose drugs have caused a deadly outbreak of fungal meningitis, the best place to start is a document titled "CPG Sec. 460.200 Pharmacy Compounding."

The four-page memo is about as exciting as the title suggests. But stick with me here: This document is important because it is the one, single piece of paper that says what the Food and Drug Administration can and can't do to regulate pharmacists who mix multiple drugs together to create a new formulation -- known, in pharmacy terms, as compounding. It tells us about the authorities they may have had in this, specific case.

The New England Compounding Center formulates this kind of medication; it created the steroid injections that have caused 14 deaths and 170 infections. They are part of an industry that, for decades, consisted of corner pharmacists creating custom doses for specific patients. It's only recently, in the late 1990s, that compounding has expanded to facilities like the NECC that focus on compounding and ship across state lines.

That's why FDA put out "CPG Sec. 460.200 Pharmacy Compounding" in 1992 (and then updated it in 2002). It spells out who should oversee compounding pharmacies in various situations -- but does so in a way that's pretty vague.

The FDA says it will "defer to state authorities regarding less significant violations of the Act related to pharmacy compounding of human drugs." The federal government will, however, step in "when the scope and nature of a pharmacy's activities raise the kinds of concerns normally associated with a drug manufacturer." That could include factors such as creating large quantities of compounded pharmaceuticals, for example.

In other words, the FDA will handle the big cases, and the states will take on the small ones. That, logistically, makes sense. It lets state pharmacy boards oversee the day-to-day operations, while bringing in the big guns for a more sweeping case.

But former FDA officials say there's also a problem here, in that the agency never drew a clear line between what counts as big and small. 

"There is no bright line," says Mary K.  Pendergast, who served as FDA deputy commissioner from 1990 to 1998. "You can't point to something to say, 'you crossed the line here.' Instead, it's a list of what to take into account."

That creates all kinds of regulatory uncertainty over who has jurisdiction over what, a challenge that could have factored into the NECC case.

"Clearly there must have been some miscommunication between the state and the FDA," says Peter Barton Hutt, another former FDA official. "If you want to use baseball terms, this is a ball that fell between two catchers. Both of them were aware of the problem but neither followed to conclusion to make sure the problem was solved. Clearly something went wrong here."

That's not necessarily how it has to be. Pendergast thinks that the agency could, for example, say that all compounding pharmacies who fill more than 50 prescriptions a month must register with the agency. That, however, would create its own set of problems: It could stretch the agency's resources too thin.

"They play Whac-a-Mole with compounding," she says. "If there’s a problem, they whack at it. That’s not necessarily an irrational approach when you consider the bigger problems they’re dealing with.”

Regulation is decidedly dull stuff. But in a case like this one, it turns out to be incredibly important. Read more on this from Lena H .Sun, David Brown and myself in today's paper.