In 2011, OSHA put out a memo that says that grain bins are not a part of farming and thus Congressional language that exempts farms of fewer than 10 employees from OSHA grain bin rules does not apply. In other words, if OSHA wants to check your grain bin, it can and will.
http://community.agriculture.com/t5/Farm-Business/OSHA-Says-It-Can-Check-Your-Grain-Bins/m-p/426905
and
http://www.omaha.com/article/20131221/NEWS/131229770/1707
The bottom line is that many small farms will simply sell out.