These are actually by OSHA, so a bit old, and a little dry – however, they can be modified as needed, updated, made more interesting, personalized, etc. These are for the OSHA 10 and 30 hour construction program. You will see two documents for each subject (sorry for not renaming them like I normally do, but there were a lot of files and I had laundry and ironing) – one is a powerpoint, and the other is a lesson guide. As such, these are good even if you are weak on a subject.
Oh – here is a previous link to the Intro to OSHA, plus Focus Four presentations: