Liver disease is often caused by drinking too much alcohol, having too much fat in the liver due to obesity or diabetes, or by infections like hepatitis B and C.
But now, scientists have discovered another possible reason why people develop liver problems.
A new study from Keck Medicine of USC found that a chemical called tetrachloroethylene (PCE), which is used in dry cleaning and found in many household products, may damage the liver.
This chemical is used to remove grease and is in products like glue, spot removers, and stainless steel polish. People can be exposed to PCE through the air, especially after picking up freshly dry-cleaned clothes. It can also get into drinking water if it leaks into the soil or is thrown away the wrong way.
The researchers found that people exposed to PCE were three times more likely to develop liver fibrosis. Liver fibrosis is when scar tissue builds up in the liver. If it gets worse, it can lead to liver cancer, liver failure, or even death.
The study also showed that the more PCE a person is exposed to, the higher their risk of liver damage. This is called a dose-response relationship—more exposure means more risk.
This is the first study to clearly show that PCE levels in humans are linked to liver scarring. According to Dr. Brian Lee, the lead researcher and a liver specialist, this finding helps explain why some people get liver disease even if they don’t drink alcohol or have other health problems like obesity.
It suggests that environmental chemicals like PCE may be a hidden reason.
PCE is already known to be dangerous. The International Agency for Research on Cancer lists it as a likely cause of cancer. Other studies have linked PCE to different cancers such as bladder cancer, non-Hodgkin lymphoma, and liver cancer.
Because of these risks, the U.S. Environmental Protection Agency is phasing out the use of PCE in dry cleaning over 10 years. However, it’s still used in some products and remains unregulated in other parts of the world.
To study this, researchers looked at data from a nationwide health survey in the U.S. called NHANES. They studied blood samples from adults collected between 2017 and 2020.
They found that about 7% of people had PCE in their blood. Those who had it were three times more likely to have liver fibrosis, no matter their age, gender, or background.
The study also found that people with higher incomes were more likely to have PCE in their blood, possibly because they use dry cleaning services more often. However, people who work in dry cleaning businesses may face even more risk because they are exposed to the chemical for long periods.
For every small increase of PCE in the blood—just one nanogram per milliliter—the risk of liver fibrosis increased five times. A nanogram is a tiny amount, one-billionth of a gram.
Interestingly, other common risk factors for liver disease like alcohol or fat in the liver didn’t seem to matter when PCE was present. Dr. Lee said this could explain cases where people are surprised to find out they have liver disease even though they don’t drink or have any other usual risk factors.
He also said PCE might just be one of many harmful chemicals in our environment that damage the liver. He hopes this study will help doctors and patients understand the risks better. If more people who are exposed to PCE get checked early for liver damage, it could lead to better treatment and a greater chance of recovery.
If you care about liver health, please read studies about simple habit that could give you a healthy liver, and common diabetes drug that may reverse liver inflammation.
For more information about health, please see recent studies about simple blood test that could detect your risk of fatty liver disease, and results showing this green diet may strongly lower non-alcoholic fatty liver disease.
The study is published in Liver International.
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