Chemicals toxic for humans, animals, and plants, including the unapproved DNOC, were found in western NSW, via a NSW Environmental Protection Authority (EPA) monitoring program.

The Macquarie Valley monitoring program ran from March 2023 to May 2024 and tested in areas including Gilgandra, Trangie, Gin Gin, and Bundemar.

The program found traces of DNOC, or dinitro-ortho-cresol, which has never been approved for use in Australia due to its harmful effects on health and the environment. 

When exposed to high temperatures DNOC can release toxic fumes. 

The indigestion of DNOC can affect the brain, kidneys, liver, and spleen. Symptoms of DNOC include confusion, fever, headache, restlessness, sweating, thirst, and/or yellow colouring of the hands, nails, and hair. 

DNOC is also harmful to birds, fish, and plants. 

Other chemicals commonly included in weedkillers, such as atrazine and diuron but should not be detected in public areas also came up in the monitoring program. 

Bulk deposition sampling capturing particles, such as dust particles that settle out of the air or are dissolved in rainwater was also used in the monitoring program. Photo: EPA

"This program was designed to detect compounds present in the ambient environment and tested for the presence or absence of more than 600 pesticides, herbicides, and insecticides to track seasonal trends and changes in pesticide use," an EPA spokesperson said. 

DNOC was found to be present along the Mitchell Highway and Mungeribar Lane in Trangie, Gilgandra, along the Castlebar Road in Bundemar, and in Gin Gin on two separate occasions this year. 

"We have reviewed results from the two detections of DNOC in March and April earlier this year and confirmed the detection was at trace levels which fits with being an unintended trace contaminant (UTC) in another product, though it is still not possible to be certain of the source," the EPA spokesperson said

DNOC has never been approved for sale in Australia and has been banned in the United States since 1991. 

It is still used in some countries to manufacture pesticides and in the plastics industry. 

DNOC used to be marketed under several names, including Derkysil, Lipan, Sinox, and Trifocide. 

"It is important to remember that the presence of pesticides in the natural environment does not necessarily mean there is a risk to the environment or human health," the EPA spokesperson said.