Kiln safety

 A kiln can have a hot breath

It breathes OUT as it is heating up and IN as it is cooling down.
It’s breath coming out of a spyhole or other opening can be very hot, so be careful where you put your eye.
When cooling, it sucks in cold air, so take care that it does not impinge on hot or warm glass in the kiln; else stress be induced into it.

UV radiation

Radiation from inside a hot kiln can be extremely high in UV. That's the stuff that does most of the damage on the beach, except that it is much stronger and can burn skin or fry an eye. UV protective spectacles are a good item to wear if peering into spyholes.

Safety catches.

Where fitted they are there because there is a reasonable perception of risk.
Thus, on Top-hat kilns using jack or brake winch lift there is a possibility of the jack or brake letting go and the hood suddenly dropping without warning.
The safety catch won’t prevent the lift device failing but if used correctly it will ensure the safety of the operator whilst working underneath.

It is interesting that clamshell kilns with lids supported by gas struts generally lack any safety device to protect the operator against a lid collapsing on them. Gas struts used on kilns are similar to those used on car boots and bonnets; and they most certainly do fail unexpectedly. One glass artist friend of mine has had a narrow escape from one such gas strut failure on a clamshell kiln.
For more, see Gas struts

Mishaps during a firing.

Sometimes, glass may crack during a firing and the release of energy may move the pieces sideways. If this happens on a kiln shelf, and particularly in kilns with wall mounted elements,  then a piece can be moved beyond the shelf edge and against the wall. Molten glass can run into element grooves and create a very expensive mess.

Leave some clearance around the edges of shelves to reduce the risk.

Hood or door interlocks.

AS/NZS3820 requires that all kilns connected to the power supply in Australia be fitted with a means of rendering it safe against electric shock when open. This is usually achieved by an interlock switch which opens when the door is opened or hood or lid is raised.
Not all overseas countries have such a requirement and it is possible that some imported kilns are not so fitted.
Be aware, especially if considering the direct import of a kiln from overseas, or if purchasing from a supplier unfamiliar with electrical safety requirements.

Correct wiring of electric plugs.

The switch in a wall mounted power outlet switches the active connection, as should do the switch on a kiln as well as the interlock switch mentioned above.
If the connections of active and neutral cables on a three pin plug are reversed it is possible that the interlock switch will not function correctly and that the elements could be live although not appearing to be so; making them capable of giving a lethal electric shock if touched.
Whilst most plugs now have active and neutral terminals marked, the cables are colour coded to more than one standard which can create confusion.
For safety sake, have the plug fitted by a qualified person.

Bead making mandrels in annealing kilns.

Some kilns made especially for the annealing of beads on mandrels allow for the insertion of the mandrel through a slot without opening a door. If the mandrel can be inserted without actuating a switch to remove power from the elements there is a risk that the mandrel could contact a live element whilst being inserted and the holder of the mandrel receive a possibly lethal shock.
The safest bead annealing kiln will have the element protected by a quartz sheath so this cannot occur under any circumstance.

Loose mounted thermocouples.

Thermocouples are frequently inserted through a hole in shell and brick or CF lining from the outside, and what can be pushed in can also be dislodged; either deliberately or by accident.
It is good practice to occasionally check that thermocouples are correctly positioned and fully inserted, as a misplaced device can make for interesting and sometimes expensive firings
For more, see How hot is that?

Spyhole plugs

At the very least the inside end of a spyhole plug will be at kiln temperature when it is removed, and able to impart severe burns if touched.
Riley kilns use a plug turned from Insulating Fire Brick (IFB) so remain cool on the outside, whatever the kiln temperature; can be removed without gloves but need some juggling if one is not to be burned when putting down. Other devices are usually made of dense clay and so are more likely to be hot all over. Who can say which is best.
Be aware and treat them as if they may bite.

Kiln unloading area.

Sounds trite, but, it helps to prepare an area to receive the contests of a kiln BEFORE starting to unload.