Metal desk frames and book racks under student desks often break, leaving jagged edges. Make sure students inspect their desks before sitting. Older desks can become loose and wobbly. Check to see if desks and chairs wiggle more than the child that sits in them.
Tall bookshelves could become top heavy and, if not secured firmly to the wall, easily pulled down. Never use a lower shelf as a step to reach higher shelves. Also, don't be afraid to ask your child's teacher if all bookshelves are secure.
Students love to run errands for teachers. However, transporting audio-visual equipment should not be one of the errands. Televisions on carts can easily topple, and recently used projectors could still be hot enough to burn.
Floor mats are nice for small reading groups, but can be slippery when stepped on. Make sure that the bottoms of mats have surfaces that cling to classroom floors.
While students should have little reason to go into teachers' desks, it's still safer to make sure that all desk drawers will not pull out all the way. Also, make sure that no sharp objects are kept in places that are not locked.