OSHA Region 1 released more details about the final determination regarding the 2014 Ringling Brothers accident that injured 9 performers.

https://www.osha.gov/newsrelease/reg1-20150423.html

Westfield High School Followup

http://www.foxnews.com/us/2015/04/25/questions-raised-after-stage-collapses-at-indiana-high-school/

http://www.usnews.com/news/us/articles/2015/04/24/more-than-12-hurt-as-stage-collapses-at-indiana-high-school

Pardon my cynicism, but I'm not sure what maintenance or inspection records they expect to find for an orchestra pit cover.  If I were investigating, I'd be most interested in the initial design of the cover and any modifications or deviations to that cover that may have been made over the years. I'd also be interested in the materials and methods of construction.