The most transparent administration in history kept things from the public to avoid controversy during the 2012 election.
From the Washington Post:
The White House systematically delayed enacting a series of rules on the environment, worker safety and health care to prevent them from becoming points of contention before the 2012 election, according to documents and interviews with current and former administration officials.
Some agency officials were instructed to hold off submitting proposals to the White House for up to a year to ensure that they would not be issued before voters went to the polls, the current and former officials said.
The delays meant that rules were postponed or never issued. The stalled regulations included crucial elements of the Affordable Care Act, what bodies of water deserved federal protection, pollution controls for industrial boilers and limits on dangerous silica exposure in the workplace.