This good question is worthy of thought. Horses are beautiful, graceful, and powerful…but are they safe? Blue Rock Horses and Farms’ motto is: Safety First, Beauty Second. This is taught to students here at the farm because:
A horse can kill intentionally. A horse can kill unintentionally.
It is hard to think in those terms, after all, they are so pretty! So are Polar Bears…
“Put your horse brain on,” is probably heard from this instructor second only to, “Keep your heels down!” For good reason. Horses do not think like humans. To be safe and stay safe around them, humans must learn the horse. Reading good horse books is a wonderful way to learn, however, observation is the best way to know horses. Watching them interact with one another is an education in itself. There is an obvious hierarchy and language among them that can be learned by careful observation. They ‘speak’ to each other in many different ways, and indeed ‘speak’ to we humans as well. So, pay close attention. And remember, it takes time to learn another “language!”
Horses are not like dogs. This must never be forgotten! Dogs are prey animals, horses are preyed animals. This is a huge and many, many times overlooked difference, and is a large factor in safety around horses. Startle a dog, it will jump, and we laugh. Startle a horse, and we may be spitting out our own broken teeth! Is this the fault of the horse? Absolutely not! Always make your presence known around the horse.

Always make your presence known around the horse.
When frightened, horses run away. That is their first natural defense. Often before fleeing they will look at what is causing the fear, then take flight. For this reason, horses need to be tied loosely so they may keep an eye out for danger (or the boogie-man, as this instructor calls it!). After-all, who wouldn’t keep an eye-out if you were someones potential lunch?

Tie and lead horses so they are able to look around and keep an eye on their surroundings.
Horses are as accurate in striking with their forelegs and with their hind ones. The safest position is either right up next to them or way out of striking distance. They have excellent aim!
So, are horses safe? Yes! Though a safe, knowledgable horseman is the best way to insure a safe horse.

Though sign was found on an old manufacturing plant, it rings true for horseman (or woman as well!).
These are minimum basics of safety around horses. Hope it helps!