How bad is it? If you want to do an experiment without spending a lot of money or wasting filament, take a 25mm Cube of Styrofoam place it on a spoon and then rig up a wire or some contraption that will hold the spoon over a candle, light the candle and make sure the distance is just far enough away from the plastic to melt the plastic in to a liquid state. Leave the room and come back in 20 minutes and ask yourself if you will be ok with that smell.
But make sure you live alone because you will be a very unpopular person with anyone else you live with. If you live in a condo or apartment complex, expect the neighbors to call the fire department because the smell is also identical to an electrical fire started by a faulty plastic appliance which often is made of ABS.
The scent of ABS comes from melting polystyrene, which is also found in Styrofoam. Is it carcinogenic? Well, there’s considerable debate about VOCs in general. Some believe that anything not from nature is harmful, while industrial chemical companies claim there’s no evidence to support this.
But chicken little aside, this stuff will give you a really bad headache and to me, no matter where one stands on the science, if you are getting sick from something, you should listen to your body and simply not do that. That would seem like common sense but as Mark Twain once said; “It should be called ‘rare sense’ because their ain’t nothing common about it”.
I can say that in my sole experiment with ABS, even with the windows open, my wife threatened to throw me out of the house if I ever printed that stuff again. The smell lingered for a few days BTW and I had active charcoal air filters going both inside the case and exterior to the case. They did not help.
I plan on rigging up a negative pressure vending system and will attempt ABS again but I will never do it without some kind of strong airflow exiting the home office.
These are the two filters I had inside the chamber and they did nothing.