At 11.15am today, a large 4000L gas cylinder begun to leak gas at the agricultural research facility on Marsden Park Road, Calala.
On arrival Fire and Rescue NSW (FRNSW) liaised with site staff and determined the cylinder was leaking from an over pressure relief valve on the top of the cylinder.
Firefighters isolated the area, switched off power supplies and evacuated 50 staff members of the Tamworth Agricultural Institute from the site.
Firefighters are now working to cool the cylinder to reduce internal temperature and reduce the pressure in the cylinder.
A bulk tanker has been rushed in for decanting. NSW Rural Fire Service and a HAZMAT team will work together to begin to decant the gas into a new, non leaking container.
The Tamworth Agricultural Institute building provides dry land research for the agricultural industries of inland northern NSW.