You should have some proof/documentation that they have taken in what you have told them in an induction. Getting them to sign it might help legally but a few questions just to ensure they have listened throughout would be better. 10 simple questions based on things like What is the plant emergency number? Where is/are the muster points? What is the site speed limit? etc etc...

What is the reason for that. i think it will depend on the complexity of the site I have come across a few companies that either require you to attend and induction meeting before being allowed on site which can be quite in depth. My old company ran an induction day that was aimed at covering as much H&S in meeting before you could take on your new job role. they covered things like fire safety, manual handling, safety across the site and other H&S matters. That way everyone had the basic training before they even started work from memory it was half a day which included a site tour and lunch. i thought it was a good way of doing the training getting it all out the way before you started your job plus you got to meet the local H&S reps and the manager who was in charge of the H&S department. Phil

I think any induction should take as long as it needs to take but as you say 45 minutes to an hour is the maximum to be able to sit still and still take in what is been trained after that people tend to glaze over and lose the will to live. Or that could just be my training method LOL. Phil

In the power, petrochem, heavy industrial sectors where I work it's unlikely to last less than 2 hours. Yes, there should be some level of interactivity such as a basis set of questions, multiple choice, etc. One or two sites I attend have an e-learning type induction that requires a set 'pass' level before you can go on site. Plant inductions should inform people of the inherent hazards, emergency numbers, emergency/ first aid procedures, resposible persons, etc.