While modern safety protocols ensure that dangerous chemicals stay out of the manufacturing of envelope glue, concerns about the health risks involved in licking envelopes have mounted in recent years. The threat of terrorist contamination, lack of government oversight and worries about public hygiene have all contributed to a general confusion over just what the dangers of licking envelopes are.
A latex allergy affects approximately 1 to 6 per cent of United States citizens and result in anything from a reddening of the skin, blistering, or nausea, to rapid heart rate, hives, and breathing difficulty. Latex is found in many envelope glues and as a result could pose a threat to people with an allergy. While the threat is usually insignificant with the licking of one envelope, people who send mass mailers, administrative professionals and others who work with large numbers of mailed correspondence would benefit from a sponge applicator.
While rare, it is possible for small pests to lay eggs or other larvae on the sticky portion of an envelope. This happens as a result poor storage conditions and sometimes as a result of negligence during manufacturing. While urban legends like cockroach jelly appearing in envelope glue have never been verified, pests including dust mites can sometimes feed on the glue and lay eggs there.
The threat of contamination can come as a result of terrorist plotting, but is far more likely to come from casual indiscretion. According to the American Society for Microbiology, 20 per cent of the American public does not wash their hands after using the rest room, handling a pet or using a public device. If the envelopes in question are in a public setting, the chances for contamination through handling are high.
The dangers of licking envelope glue have been blown out of proportion, with numerous urban legends and campfire stories; while relatively little attention is paid to the paper. The paper on the "licking edge" of an envelope has been semi-blunted and curved in order to make paper cuts difficult to acquire. Still, the threat of paper cut exists and can, in conjunction with contamination, lead to infection and difficulty eating.
Malpractice is a possibility, even while it goes unnoticed by the general public. Reports of using mop water to thin the glue have as yet been unverified, but the possibility of negligence on the part of the manufacturer is always a danger. Malpractice opens the doors to many other dangers including infestation and contamination.