SYDNEY, April 17 (Xinhua) -- Wildfires near urban areas are an escalating threat to drinking water safety, water quality experts from the University of Technology Sydney (UTS) warned on Thursday.

Researchers from the UTS Center for Technology in Water and Wastewater highlight how fires can contaminate drinking water distribution systems, posing serious public health risks.

Nearly half a billion people worldwide have experienced wildfires within one kilometer of their homes over the past 20 years, said the researchers, calling on areas affected by recent blazes, such as the 2025 Los Angeles fires, to urgently test and monitor water supplies for contamination.

"Water must meet safety standards before leaving a treatment plant, but contamination can occur during transport," said the research letter published in Science.

Wildfires can degrade plastic pipes or cause smoke to infiltrate depressurized systems, introducing harmful volatile organic compounds (VOCs) into drinking water, it said.

More than 50 VOCs, including carcinogens like benzene, have been detected in water networks following wildfires, said lead author Li Xuan, citing the example that 11 months after the 2017 Santa Rosa fire in northern California, benzene levels in local drinking water remained at 40,000 micrograms per liter, far above safe limits.

Even brief exposure to just 26 micrograms per liter can harm children, while long-term exposure increases the risk of leukemia, Li said, adding these contaminants often go undetected, particularly at the consumer end of the network, leaving communities unaware of the danger.

Co-author Prof. Wang Qilin warned that climate change and expanding urban development are heightening wildfire risks and, in turn, the threat to water safety, urging governments to identify wildfire-related contaminants, establishing safety limits, and enforcing robust monitoring protocols. ■