Question: I have been using scrub free on tubs, toilets, and showers for years and I see it contains sulfamic acid.  Is this harmful?  I have been getting a rash during spring and summer that is very itchy. Doctors have not been able to help.

Sulfamic acid is a powdered acid that is commonly used in household cleaning products.  In it's powdered form, the hazards of the product are understated by most manufacturers.  When added to water, however, it basically becomes sulfuric acid, which is a highly corrosive mineral acid.  Sulfuric acid is quite hazardous and toxic, and is serious overkill for removing hard water stains from toilets, tubs and showers.  Another concern is that if it is not inhibited properly, sulfuric acid can seriously and irreversibly damage tile, grout and fixtures.

We can only speculate that in the spring and summer the heat and humidity are at elevated levels.  Please do not take this personally, but you probably have more moisture and sweat on your arms and hands during that time.  The dust from the cleaner settles on your arms and the moisture activates the sulfuric acid.  This small amount of acid deposited on your arms is not substantial enough to cause chemical burns to the skin (thus the doctors cannot really detect anything), but would be enough to cause irritation and itching.  My guess is that during the fall and winter, there is less moisture on your arms and you might be wearing a long sleeve shirt that protects the skin from this dust.

NEU Homecare is currently developing a tub and tile acid cleaner that is not corrosive to skin.  While still acidic enough to remove hard water deposits, it will not burn skin (although eyes will still need protection).  That product should be out sometime in the next couple of months.

In the meantime, household vinegar should be acidic enough to remove most hard water deposits and rust stains.  Unlike the advice of some self-proclaimed cleaning experts, we do not recommend that you mix the vinegar with anything.  It is milder to use than sulfamic acid.  It is still an acid, so be careful when using it.  

Otherwise, if you really want to stick with the product you are using (we do not recommend that), you could wear a long sleeve shirt year round when cleaning in the bathroom.  If you wear short sleeves, make sure you rinse your arms, hands, and face after using the sulfamic acid-based product.  Make sure all powder traces are removed with fresh water rinsing.  Also, keep in mind that you may want to wash any clothing that has the traces of sulfamic acid on it because those could be transferred to other people and surfaces through contact.
 

We hope this helps.  Thanks again for your interest in NEU Homecare safe cleaning products for the home.
 

Sincerely;

The Formulation Chemist™

Actual question & Answer submitted to: www.neuhomecare.com