Message: Hello,

We accidentally split a bucketful of dilute hypochorite bleach on our vinyl floor. It seeped under the vinyl and into the adjacent synthetic carpet, Our efforts to remove the contamination with copious amounts of water have proved inadequate because we all ( adults and kids) have burning feet and hands from bleach exposure. We think it has been spread to many hard surfaces in the home.

We write to ask your advice on how to neutralize the hypochlorite bleach on these various surfaces and return our home to a safe condition.

Your advice will be much appreciated.
Many thanks and kind regards, Kelly 

I would recommend that you contact a poison control center right now. They have a lot of extremely useful information for problems like this, and you are certainly describing a case of contact poisoning. This telephone number will reach the National Poison Control Center from anywhere in the US: 1-800-222-1222. The information below is correct according to my best knowledge, but I think that it would be best for you to first contact the poison control experts and follow their advice.

Be careful not to use any strong acid, nor any cleaner that might contain ammonia, since both of these will generate deadly gases when they contact the spilled hypochlorite. The gases produced can cause serious injuries or death. Vinegar, a weak acid, is not a good choice for neutralizing hypochlorite.

My choice for neutralizing a household spill of hypochlorite bleach would be to use hydrogen peroxide, because it safely neutralizes the hypochlorite without releasing irritating sulfur compounds into the air. 

Two other good choices for neutralizing hypochlorite, Anti-Chlor and Bleach Stop, both contain sulfur, which not only smells bad but can trigger breathing problems in people who have asthma, though I think that they are safer than the hypochlorite you're now dealing with. An MSDS for sodium thiosulfate (Bleach Stop) at JT Baker indicates that it can cause coughing and shortness of breath; an MSDS for sodium bisulfite warns that it can cause respiratory reactions, and it releases toxic sulfur dioxide gas. 

Hydrogen peroxide does act as a bleach on some materials, in some cases removing color, but that's a minor consideration when what you need is to neutralize toxicity. You can buy it at your neighborhood pharmacy, where it is sold as an antiseptic. The 3% strength is certainly strong enough, probably stronger than you need. It sounds like you will need a great many bottles. It is dilute enough to be safe to use directly on your skin. The bubbles of gas that it produces are pure oxygen.

How much hydrogen peroxide will you really need? If your bucketful contained one cup (250 ml) of the usual 5% hypochlorite household bleach, that amounts to 12.5 grams of pure sodium hypochlorite, or about 0.17 moles (a unit referring to a number of molecules). Since one molecule of hydrogen peroxide is required to react with one molecule of sodium hypochlorite, that amount would require about 6 grams of pure hydrogen peroxide, which works out to 200 ml. If my figures are correct, then, you would need almost one cup of 3% hydrogen peroxide to neutralize each cup of 5% hypochlorite household bleach you started with, before diluting it. I am sure that you will want to err on the side of using too much, since it will be difficult to reach every bit of spilled bleach. You don't have to worry about the hydrogen peroxide persisting in the environment, as it tends to break down fairly quickly.

For additional information, see How can I neutralize the damaging effects of chlorine bleach?

I hope this information is helpful to you. Please let me know what happens.

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