Industrial inkjet coding marks every product moving through a line with a date code, lot code, or identifier. Most of the inks doing that work are solvent-based, built around MEK, acetone, ethanol, or proprietary carriers that flash off as the ink dries. On a single coder the vapor load is small. On a packaging hall running multiple lines around the clock, those vapors accumulate in the air operators breathe and on the products they coded twenty minutes ago. In food and pharma facilities, that crossover becomes both a compliance issue and a quality complaint.