This article is from the Baby Proofing FAQ, by Sandra Smith, firstname.lastname@example.org with numerous contributions by others.
From: Tom McBrine
We have a fairly large hearth on our fireplace (8' long, 2 1/2' deep and
at least 8" high). What we did was build a wood cap which incased the
hearth on 3 sides, padded it with 1" styrofoam, and covered it with
contact paper in a color that matched the rug in the room. Due to it's
weight, there's no need to anchor it down. It ain't going anywhere!
You can't have fires, but it has really saved our kids from serious
injury. Just the other day our oldest, Jenny (2 1/2 yrs), tripped on a toy
and when she fell her forehead struck the front corner of the padded
hearth. She cried from the impact, but there wasn't a scratch on her.
This is a good example of why I feel teaching a child to avoid the hearth
isn't good enough. Accidents do happen!