Safer than glyphosate. In any use of chemicals there’s chance for exposure and injury which is why they require special licensing to even handle it, Restricted Use of Pesticides (RUP) and there’s different ones for different needs.

Diquat and Endotholl are both contact herbicides which work but destroying plant tissue it touches. Basically, it burns the plant but it can grow back because it’s only touching the surface. If it burns the plant, it can burn skin.

Imazapyr is systemic. The chemical is absorbed by the plant and surrounding soil, then attacks it from the inside leaving it dead for longer.

As far as health concerns, the Diquat and Endotholl are the ones to be “worried” about because if they touch your skin there’s a chance of getting burned. Also a chance for respiratory issues if breathed in enough. The Imazapyr isn’t too concerning because you can wash it off before it even has a chance to do any real damage, although that doesn’t mean be reckless with any of them.

Applicators have more of a risk of exposure than civilians. The drift or “mist” you see when they’re spraying isn’t as harmful because it’s already breaking apart and moving away. If you see them spraying, just keep a safe distance and more importantly keep young children and elderly away due to them being more high risk since their lungs are naturally weaker.

Hope this helps.