Bednobs - bleach is caustic. I've seen some nasty burns when it's not been used safely.
Mattk, yes, your son should be provided with suitable gloves if he's handling bleach. It's then his responsibility to wear them. He should also have been provided with information on basic emergency and evacuation procedures on his first day before starting work. This is the law. Bear in mind, though, that it's also his responsibility to familiarise himself with such things as fire notices and other emergency information posted on noticeboards or otherwise made accessible - but of course, he needs to be shown where they are.
His rights to safe conditions do not depend on whether or not he has a contract, nor even whether he's being paid.
Have a browse around the HSE website:
http://www.hse.gov.uk/ - they may be able to answer a few questions for both of you.