UPDATE: New York Department of Environmental Conservation Commissioner Joe Martens has responded to Shah's letter with a statement of his own. In that statement Martens says Shah's delay "does not necessarily mean that the issuance of permits for high-volume hydraulic fracturing would be delayed." You can read that statement, and see a video explainer of the hydrofracking review process, in this Innovation Trail web post from Marie Cusick.

Shah added that the time to investigate health effects is before a state allows drilling – something he says other states haven't done. The investigation has focused on drinking water contamination, as well as on issues including air quality and "community impacts."

Without Shah's health review, the state won't be able to issue its environmental impact statement tomorrow. That means the state will miss a Feb. 27 deadline for releasing its fracking regulations…and will have to reopen the rules for public comment for at least 45 days.

Shah said in the letter he expects to deliver the completed Public Health Review within a few weeks, along with his recommendations.

You can read the full letter here; and we'll have more on this story tomorrow morning on the 8 O'clock Hour.