Personnel from NSW Fire and Rescue and the State Emergency Service (SES) were put through their paces during Monday night's exercise, which involved containing and disposing of hypothetical contaminants that had made their way out of a drain near Ollie Robbins Oval and into the river.

That and the unlikely but nevertheless frightening possibility that a truck fully-laden with liquid cargo could run off a bridge and spill chemical into the river were among scenarios the exercise aimed to prepare emergency personnel to tackle.

During the exercise, personnel used compressed air to inflate booms, floating tubes that were joined to form long snake-like barriers that could be attached to boats and towed out onto the river and anchored to surround and contain chemical spills.

Dubbo had six such booms that totalled 120m, enough to stretch the width of the river.

Bales of hay were another option that had been used to catch spills.

Once the booms had been used they were brought back in, cleaned, deflated and stored.

The SES boat, which was equipped with a global positioning system, depth sounder and radio facility, could be hooked up and lifted by a helicopter across drier patches during floods. Operators were trained to launch them from the most difficult of conditions, including rock ledges or where rescues needed to be performed in partial scrub.

Personnel were also given a demonstration of how the Megator pump and a skimmer worked to suck up river water as to separate pollutants and collect then in a drum to be safely disposed of.

Also on-site for the exercise was the HAZMAT (Hazardous Materials) van, which was equipped with a computer for personnel to send and receive information about potentially hazardous chemicals firefighters might encounter during emergencies.

Inside was a weather station for firefighters to monitor humidity, wind and temperature when they arrived at hazardous materials incidents. The van stored specialist protective clothing including spillage suits, boots, waders and safety vests.

Boats belonging to the HAZMAT and SES units were used during the exercise, NSW Fire and Rescue Senior Firefighter Scott Habgood explained, as what was used depended on availability and the fact different boats were suited to different jobs.

"Working with the SES is important because they really are the boat experts so if they can handle that part of the emergency we can focus on the contaminant response," he said.

"It makes sense to carry out the combined training exercise because we will be working together in the event of an emergency of this type."