Can your customers rest assured that there's no trace of a foreign element in the chemicals you produce? You might think that there's no real risk in a little bit of mixing between products, but using printing technology, you can design warning labels that address this specifically.
Even a relatively harmless-seeming additive, like water, can be dangerous if it shows up in the wrong place. A letter from a frustrated consumer that appeared in ABC news recently detailed the problems caused by a gas pump that had its fuel contents diluted by water.
Although this was said to have been caused underground, and not because of a labeling mix-up, the right chemical labels could be used in a similar situation when there might be a risk of excess amounts of water.
Another good point brought up by this article concerns the way outside standards apply to the problematic elements. In this situation, the ABC correspondent responding noted that state laws permit some water to exist in a commercial gas storage supply. This might apply to other chemicals or naturally occurring flaws that you need to watch out for. Displaying the appropriate standard on your chemical labels can help you walk that fine line.
In some cases, of course, surprise additives can be extremely dangerous. NPR has reported on the way that the chemical "1, 4-dioxane" has become a very real hazard for the water supply of West Virginia.
As soon as a possible danger is discovered, the possibility needs to be identified, corrected, and upheld, and adequate printing solutions can aid in getting the word out.