Sydney: Over one-third of schools in Australia's Queensland state have detected a threat to students' health due to the presence of the deadly carcinogenic substance asbestos in the school walls.

Of the 289 schools inspected by the state education department, the substance called asbestolux - made of 70 percent asbestos - was detected in 115. Around 1,400 schools in the state remain to be checked.

People exposed to asbestos in their workplace or their homes are prone to breathe in tiny asbestos fibers released into the air, which may get trapped in the lungs and cause inflammation and breathing problems.

Exposure to asbestos may increase the risk of lung cancer, gastrointestinal and colorectal cancer and sometimes throat, kidney, oesophagus and gallbladder cancer.

Liberal National Party education spokesman Bruce Flegg questioned Education Department director general Julie Grantham, who confirmed the substance was found in 6.9 percent of the school walls tested.

"This substance should have warning signs placed on it wherever it is found," Flegg said.

According to a study by the workplace health and safety department, asbestos fiber boards were used for wall and ceiling panels in high-humidity areas in the country in the 1950s and 1960s. IANS