Following bleach with an alcohol sanitiser

Does it work?

Does not work

Refuted as a safe or effective practice on a state health department's do-not-mix list. Only one authoritative source carries the chloroform finding — that is enough to warn on, since the cost of an unnecessary rinse is nothing, and it is not enough to claim the hazard is as well documented as the chlorine reactions.

This is a verdict on whether the technique is effective. Whether it is safe on a particular surface is a separate question, answered below.

Where not to use it

Why it works

The claim assumes the two disinfectants act independently and additively, each killing what the other missed. Hypochlorite instead reacts with alcohols to produce chlorinated organic compounds including chloroform, and it does so without heating or unusual conditions. The reaction consumes both products, so the additive disinfection the technique is reaching for does not occur either. As with the acid reaction, the common route is sequential rather than simultaneous: the first product is applied, not rinsed, and the second goes onto the same wet surface — which is combining them, with the surface as the vessel.

Background

This is not a hack so much as a habit, and it became a common one: wipe a surface with bleach, then go over it with an alcohol sanitiser or wipe, on the assumption that two disinfectants are more thorough than one. Neither product is being mixed in the ordinary sense, and nobody performing it thinks of themselves as combining chemicals. A state health department hazard alert nonetheless names the pair — bleach with rubbing alcohol forms chloroform, with reported effects of dizziness, nausea, headaches and loss of consciousness. Losing consciousness in the presence of the reaction that caused it is what makes this worse than the symptom list suggests, since the exposure continues while the person cannot leave. The practical point is that isopropyl alcohol is the active ingredient in a great many surface wipes and hand rubs, so a reader can perform this without having seen the word alcohol on anything.

What it does not do

• One authoritative source states this hazard, on a list rather than as its main subject, and no second source states it
• Rinsing thoroughly between products removes the hazard, and is the answer wherever both are genuinely needed
• Disinfection requires a specified period of wet contact regardless, so a surface wiped and immediately dried has not been disinfected by either product

What to use instead

• Detergent — A surfactant-based cleaner. The general-purpose answer for greasy and particulate soil, and the correct first choice far more often than any specialist product.
• Rinsing and drying — The step people skip, and the one that decides whether cleaning protected the surface or damaged it. Residue left behind is exposure that continues after you stop.