The public is being warned a contingency plan is in place to protect them as up to 900 firefighters go on strike.
The walkout in Essex is over proposed cuts, staffing levels and working conditions.
The county's fire and rescue service says more than one hundred firefighters are still working.
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Wednesday lunchtime's weather for the east of the region
Wednesday lunchtime's weather for the west of the region
There is a high risk from birch pollen during any good weather. Oak pollen is also on the increase.