Around 60 firefighters battled overnight to put out a large blaze in a straw barn at Cessford Farm near Morebattle, Kelso, on Sunday night.
The 14 crews took 15 hours to extinguish the fire in an estimated 75 tonnes of straw bales.
Group commander William Allison, a fire officer with 29 years’ experience, who co-ordinated the service’s response said: “It was quite a large incident.”
Firefighters were called to the scene at about 12.45am by farmer David Thomson.
Kelso teams were the first on the scene: “It was well alight when they arrived,” said Mr Allison.
Officers from Galashiels, Livingston, Jedburgh, Lauder, Hawick and Coldstream also attended, and three pumping appliances were used.
Hazardous materials experts from Edinburgh also attended when officers found the shed roof was asbestos.
Firefighters in breathing apparatus, supported by improvised ground monitors and by crews dedicated to providing a continuous water supply, worked in shifts throughout the night.
Mr Allison said: “We had measures in place to mitigate any damage to the environment and for the safety for our crews: we put cordons up and inform SEPA, and we also try to stop any spread of asbestos fibres by using a fine water spray.
“It was very successful. It was resource intensive and the fire lasted well into the next again day. The fire was under control within a couple of hours, but it then burns for a while. It took us about 15 hours to extinguish it.
“We were lucky there was a hydrant supply, there was ample water in the vicinity.”
There were no casualties.
Mr Thomson did not wish to comment when contacted by The Southern on Tuesday.
Mr Allison said: “This is the first straw fire of this current harvest season. We have had a number of (such) fires in the Borders over my time, but they are reducing and that’s down to the close co-operation between the fire and rescue service, and the National Farmers Union and farmers.
“It’s been a dry summer and we would always encourage any farmers who want advice to phone us and we would be happy to give out any advice on farm risk assessment.”