Hines Hill chemical spill: Great Eastern Highway blocked off after trailed detaches from truck

Firefighters are responding to an unfolding emergency in Hines Hill, where chemicals have spilled onto Great Eastern Highway after a trailer detached from a truck.

The trailer was carrying liquid ammonium nitrate — a chemical compound commonly used as a fertiliser and in explosives in the mining industry — when it came loose near Neening Road on Monday afternoon.

The runaway trailer then flipped, spilling the chemicals onto the roadway.

Road blocks have been put up around a 3km exclusion zone from the upturned trailer.

A Department of Fire and Emergency Services spokesperson confirmed several crews were at the scene of the spill, including two from Merredin Volunteer Fire and Rescue Service.

They have made the area safe and are now working with the help of WA Police officers to reopen the road as soon as possible.

Main Roads WA was also advised of the incident.

No injuries were reported.