What Are the Risks of Cleaning With Bleach and Other Disinfectants?

Nov 29, 2023

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Our use of antimicrobial cleaners spiked during the pandemic. Given the potential long-term health risks, it might be worth cutting back again.

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By Dana G. Smith

The cleaning industry experienced a boom during the first years of the pandemic. Covid-19 cleaning protocols in schools, stores and other public spaces ratcheted up, with a spray and a wipe-down becoming de rigueur on every surface after every use. Fear of the coronavirus also prompted people to use more disinfectant wipes and sprays in their homes, and consumer spending on cleaning products increased 12 percent between 2019 and 2021. (The New York Times admittedly contributed to this disinfecting frenzy.)

We now know that the extra cleaning was unlikely to have helped limit the spread of Covid-19, but it did increase people's exposure to the chemicals used in those products — some of which may be hazardous to health. Experts worry that repeated inhalation or skin contact can be harmful over time. Calls to poison control centers about cleaning chemicals also increased during the pandemic, primarily for accidental or intentional ingestion.

In some instances — like the start of a new and mysterious pandemic — the immediate risk of infection is pre-eminent and outweighs any future potential consequences from chemical exposure. But since we now know that disinfecting isn't likely to protect us from Covid, it's worth taking stock of whether the risks of using certain cleaning products are greater than the rewards. Crucially, the experts we spoke to for this story said that simple soap and water is sufficient for regular cleaning.

Here's what to know about the safety risks of the most common antimicrobial chemicals and how to reduce your exposure while keeping your home hygienic.

Disinfectants are commonly found in all-purpose surface cleaners marketed for use in kitchens or bathrooms. Think 409, Lysol sprays, Clorox wipes or anything else that says "kills 99.9 percent of germs" on the label.

The most prevalent disinfecting chemicals are quaternary ammonium compounds, also known as "quats" or Q.A.C.s. Their chemical names typically end in a variation of "ammonium chloride," such as alkyl dimethyl benzyl ammonium chloride or the snappier benzalkonium chloride.

The other main types of disinfecting chemicals are chlorine-based products, namely bleach (sometimes labeled sodium hypochlorite); different types of acids, like citric acid, hydrochloric acid or lactic acid; and hydrogen peroxide.

Knowing what's in a cleaning product can be tricky because the federal government does not currently require companies to list chemicals on labels. In 2017, California passed legislation demanding clearer product listings, and the American Cleaning Institute, which represents the U.S. cleaning products industry, told The Times it was lobbying for legislation to regulate labeling nationally. In the meantime, you may have to look up ingredient lists online using brand websites or resources like SmartLabel or the Environmental Working Group's product guide.

The health risks cleaning chemicals pose are hard to pin down because exposure is difficult to quantify, and many of the commonly attributed conditions — like asthma, cancer and infertility — take years to develop. Some of the research that exists has been done in professional fields to determine whether certain health problems are more prevalent in people who have higher exposure levels, like janitors and nurses. Other studies conducted on mice aim to more directly test whether certain chemicals cause negative health outcomes, but findings in animals don't always apply to humans.

According to the currently available research, the most concerning disinfecting chemicals are the ones used most often: Q.A.C.s and bleach.

In professional settings, Q.A.C.s have been linked to skin irritation, asthma and other lung problems. For example, several studies found that nurses who frequently use the chemicals to disinfect surfaces and medical equipment had higher rates of asthma and C.O.P.D., although other research did not find a significant association. A 2021 study found that the presence of Q.A.C.s in human blood was linked to disrupted immune and metabolic functions. In mice, exposure to Q.A.C.s decreased fertility.

A series of recent papers found high levels of Q.A.C.s in the dust in people's homes, in blood samples and even in breast milk. The researchers measured levels of several different Q.A.C.s common in cleaning products and compared the amounts present in 2019 and 2020. Q.A.C.s were detected in a vast majority of samples, and in the dust and blood studies, the levels rose by an average of about 70 percent after the pandemic started. The more often people used disinfecting products in their homes, the higher their Q.A.C. levels were.

"When we started seeing them in each and every sample and at high levels, we were really surprised," said Amina Salamova, an assistant professor of environmental health at Emory University, who led the research. "Exposure to Q.A.C.s is widespread, which was the case before Covid as well, but it definitely has increased since the pandemic."

Whether household Q.A.C. use causes the same problems seen in professional settings is an open question. "We need larger studies to look into potential outcomes in the general population, in nonoccupational settings," Dr. Salamova said. "That's a huge gap in the research."

There are also concerns that Q.A.C.s could contribute to antibiotic resistance in bacteria. Partly for this reason, one Q.A.C., benzethonium chloride, was banned by the Food and Drug Administration from being used in hand sanitizers, as was the disinfecting agent triclosan.

In light of this mounting evidence, several health and environmental groups have flagged Q.A.C.s as chemicals of concern. A Massachusetts science advisory board recently recommended adding Q.A.C.s to a list of regulated toxic or hazardous substances, and California added them to its biomonitoring program. The E.P.A., which regulates Q.A.C.s as pesticides, classifies the chemicals in its second-highest toxicity category for oral and inhalation exposure.

Bleach is a more familiar disinfectant to many people, but experts have raised concerns about its safety as well.

"It's hard not to talk about it," said Samara Geller, senior director of cleaning science at the Environmental Working Group. "It's in every cleaning product, practically." The chemicals in bleach "are persistent in the environment, and they’re also very corrosive," she added.

Bleach's corrosive nature means that it can be damaging to skin and eyes if contact occurs. It has also been shown in numerous studies to be linked to asthma, among professional cleaners as well as people who use it frequently in the home. Diana Ceballos, an assistant professor in the department of environmental and occupational health sciences at the University of Washington, said that one of the American Lung Association's "recommendations on how to avoid asthma or prevent asthma or ameliorate asthma" was to avoid using bleach.

A risk unique to bleach is the potential for producing toxic gases, namely chlorine gas, which has been used as a chemical weapon. The reaction occurs when bleach is mixed with ammonia — which is found in many glass cleaners, oven cleaners and some all-purpose cleaners — or acids, including vinegar.

In 2020, poison control centers reported more than 5,000 cases of cleaning-related chlorine gas exposures, two of which were fatal. In one case, a woman died after mixing a bleach-based cleaner with an acid-based toilet-cleaning tablet. It's critical to never mix bleach with another cleaning product unless you’re absolutely positive it doesn't contain an ammonia or an acid — which, considering products are rarely clearly labeled, is hard to know.

Most of the experts The Times spoke to for this article said that they rarely, if ever, use disinfectants when they clean their homes, instead opting for soap and water. They also advised swaps to safer ingredients, such as disinfecting products that use hydrogen peroxide or citric acid. (Check out the E.P.A.'s Safer Choice program for more alternatives.)

"We definitely recommend people substitute with some D.I.Y. recipes instead of buying products off-the-shelf," Ms. Geller said. "Even a dash of dish soap with a bit of baking soda can help remove that scum off your sink or out of your bathtub, and that can really help you to avoid some of the heavier, harsher chemicals."

There are rare moments when harsher chemicals might be warranted, like if you’re battling an outbreak of norovirus in your home. If you do use a disinfectant, opening a window and turning on a ventilation fan can help to reduce your exposure, as can wearing a mask and gloves when you clean.

"Especially since Covid, a lot of people use a lot of products, and sometimes not safely," Dr. Salamova said. "So I would recommend, no matter what products people use, to follow the guidelines and use them safely."

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