is it safe to work with without wearing a respirator?
I’m not sure if it’s safe but I always wear my respirator anyway. I think the Tamiya paint is paint resin particles suspended in some sort of alcohol solution. It’s not as bad as lacquer based paint but it can’t be good.
Tamiya is essentially acrylic resins in alcohol. It’s as safe as paint can be,which doesn’t mean much. Only water paints are safer, though of course completely useless for painting styrene.
A respirator isn’t necessary for hand brushing, unless you have an allergic reaction to the paint (rare), but airbrushing paints atomizes the paint and breathing in atomized paint can’t be good for you. I have a spray booth that works very well and I don’t use a respirator unless I’m using rattle cans (I never spray enamels or lacquers). If you don’t have a booth, then use a respirator. At the very least those paper masks.
“Safe” is a loaded term.
Tamiya acylics are made from liquid acrylic resins and pigments, and one of the primary solvents appears to be alcohol, as Bill said. They pose little hazard when hand painting.
Anything in aerosol form, say from an airbrush, is more readily absorbed through the respiratory system. While acrylic paints are generally less hazardous than enamels or lacquers when in aerosol form, that does not mean they are completely harmless. A spray booth is highly recommended for spray application of any coating. In the absence of a spray booth, I’d use an organic vapor respirator, and make sure that the room air is exhausted outside the house, or do my spray painting outside.
DO NOT USE A DUST MASK. A dust mask only protects you from particulates, not from vapors. It also has the potential to concentrate the vapors breathed by the wearer.