Primer Residue/Gun Shot Residue.
Common primer mixtures include compounds of lead, antimony and barium.
The metal lead (Pb) is poisonous to human.
Rapid heating and confined pressurization during cartridge discharge lead to aerosolized accumulation of heavy metals. The primer temperature exceeds the vapourization points of lead (1620oC), antimony (1380oC) and barium (1140oC) within fraction of millisecond. Due to supersaturation, the primer vapors often condense and liquefy onto the primer surface as droplets which have a characteristic morphology and chemical composition.
Generally, inhalation of airborne lead may result in absorption rate of about 50% whereas absorption of ingested lead approaches 10%.
The primer as well as the projectile is the two main sources of airborne lead.
80% of airborne lead on a firing range originates from the projectile while the remaining 20% comes from the combustion of the primer mixture. However, the latter is more hazardous due to the formation of finer particles size as compared to those scrubbed from the bullet surfaces because these finer particles have greater absorption rate through the respiratory tract.
I would advise to wash your hands as soon as possible, and washing your hands, forearms and face before eating.
Below is a pdf from the CDC
Link Removed