Maldon fire fighters were drafted in to help tackle a chemical leak at a food factory.
They were among crews from Witham, Chelmsford and Colchester to tackle to leak in Bury Lane, Hatfield Peverel last night.
A 200 metre exclusion zone was put in place and residents in the area were advised by police to keep their doors and windows closed.
No one was evacuated and there were no casualties.
Crews were called to Arla Foods after workmen reported chemical vapours spilling from a bulk storage container.
The tank contained hydrochloric acid and staff on site wearing respiritory equipment were withdrawn from the building for their safety by crews arriving at the scene.
Fire fighters set up a decontamination zone so that they could redirect the acid by operating a valve on its tank.
They donned gas tight suits to carry out the operation.
The area was made safe in the early hours of this morning and the site was left in the care of staff and the Environment Agency.
British Transport Police were informed of the incident because of the proximity to the railway.