Nothing about Richard M. Nixon was simple. Not the man; not the presidency; and certainly not the legacy he left on OSHA.
On the one hand, the Nixon Administration founded OSHA. In addition to signing the law that brought OSHA into existence (the Occupational Safety and Health Act of 1970), President Nixon made great efforts to establish the agency as a credible and effective enforcement authority. Nixon's OSHA waged an aggressive program of inspection and fines.
The Nixon Administration also developed OSHA's rulemaking capacity. It was under Nixon that OSHA promulgated its first standard, covering asbestos fibers. In fact, OSHA rulemaking during the Nixon years was criticized for being overly aggressive and for publishing rules without sufficient input from industry.
But Nixon's OSHA also had a dark side. In 1974, at the height of the Watergate crisis, Congressional investigators unearthed an internal memo from 1972 in which senior administration officials discussed ways to tailor the OSHA program to gain support of the business community for the President's re-election. Among other things, the memo suggested that OSHA go easy on companies that contribute large sums to the President's campaign.
There's no evidence that this talk actually affected OSHA's activities. But it took the agency years to recover from the damage inflicted on its reputation by the so-called "responsiveness program."