National School of Occupational Health [1], part of Health Education England.
This includes some on-line lectures.
Access to this requires registration and a log-in.
UK Health & Safety Executive [2]
This has a lot of guidance on many topics on health & safety hazards, legislation, control methods, health surveillance.
US Occupational Health Safety Administration [3]
This is a large internet based resource which has a variety of guidance information, including some videos.