I used to manufacture methylmethacrylate, as well as acrolein (which is often co-produced with MMA). These are among some of the more toxic chemicals currently manufactured in the USA.

Acrylates in general are truly awful. Our guys died with their faces boiling and breathing in their own vomit while also still vomiting. From a relatively brief exposure.

A bigger public risk of MMA is actually the extremely low odor threshold (in the parts per billion). The god-awful smell can make an area temporarily "unlivable" even below any known health thresholds. And it affects very large areas, because of the very low odor threshold.