OSHA might be the only federal regulatory agency that has attempted to keep its activity within the rules mandated by Congress.
The US EPA is quite different in that aspect. EPA constantly pushes its authority and expands its power, using indirect means to achieve meet an agenda only known to selected personnel within the administration.
I believe that much of the OSHA backlash is due to Congress' inability to reign in the EPA. OSHA is a sitting duck and the OSHA administrators seem to fail in efforts to grow the agency's Congressional power base.
The EPA nurtures its relationships with Congress and socialist environmental groups. It has a strangle hold on academia by awarding research grants aimed at supporting its increasing regulatory agenda.
OSHA bases regulatory needs on hard data. EPA bases its regulatory actions on risk assessments and biased, federally funded studies which cost the tax payers billions of dollars.
Members of Congress expend every effort not to attack the EPA and be identified as being anti-environment. One would think that OSHA would have more power considering that it is a part of the Department of Labor, which has burdened employers with so much regulation and litigation that I often wonder why any employer would want to remain within the US regulatory system. OSHA desperately needs a very strong, determined and savvy administrator (i.e., one with common sense and relationship skills).
The fact that EPA has cabinet rank and OSHA does not will always be a problem for OSHA. I was always impressed that OSHA managed to meet the letter and intent of the OSH Act without overwhelming backlash. I think that changed with the Standards Completion Project. The great mistake was the proposed ergonomics standard for which it was known that they didn't have enough backing before they started the project. It isn't a heavy-handed organization, although some would disagree. EPA is dictatorial, and I am being kind with that assessment.