Well, that really depends on whether or not you know the effects of what you are working with. It is really easy to be careless with such things when folks don't really know the effects. Even when she died, she didn't say much about the radiation effects.

Heck, we used xrays to fit shoes on people long after she died.[1] I'm sure part of that was humans being slow to regulate it, but still.

Knowing that x or y substance is dangerous brings a different perspective, I think. By the time I worked with formaldehyde, we knew we needed some precautions. I also think it is wise to consider age and mental capacity: IF someone isn't old enough to have full adult rights (including drinking, warring, and renting cars) they probably shouldn't be able to decide to not be careful. But then again, by the time one is educated to today's standards, they are old enough.

[1] https://en.wikipedia.org/wiki/Shoe-fitting_fluoroscope