People with exposure to a synthetic chemical found widely in a range of consumer and industrial products were 4.5 times more likely to suffer from non-viral hepatocellular carcinoma the most common type of liver cancer, according to a new study.

The chemical, called perfluorobutane sulfate or PFOS, is one of a class of man-made chemicals called per- and polyfluoroalkyl substances, or PFAS. These chemicals are also called forever chemicals because they break down very slowly and accumulate in the environment and human tissue, including the liver.

Researchers from the University of Southern California's Keck School of Medicine found evidence that PFOS appears to alter the normal process of glucose metabolism, bile acid metabolism and the metabolism of a type of amino acid called branched-chain amino acids in the liver.

The disruption of normal metabolic processes in the liver can cause more fat to accumulate in the liver, a condition known as non-alcoholic fatty liver disease, or NAFLD. There has been a dramatic and unexplained rise in NAFLD around the globe in recent years, which is concerning because people with NAFLD have a much higher risk of developing liver cancer.

Prior research in experimental models has suggested that PFOS exposure increases the risk of liver cancer, but this is the first study to confirm an association using human samples. "This builds on the existing research, but takes it one step further," said Jesse Goodrich, Postdoctoral scholar at the University of Southern California's Keck School of Medicine.

"Liver cancer is one of the most serious endpoints in liver disease and this is the first study in humans to show that PFAS are associated with this disease," she added. The team involved 50 participants who developed liver cancer, evaluated their blood samples taken prior to their cancer diagnosis and compared them with 50 people who did not develop cancer from the same study.

Researchers found several types of PFOS in the blood samples that were taken before the participant developed liver cancer. The participants in the top 10 per cent of PFOS exposure were 4.5 times more likely to develop liver cancer than those with the lowest levels of PFOS in their blood.