Firefighters are spending a fourth day at the scene of a fire on an industrial estate in Newhaven where 200 tonnes of rubbish are alight.
The blaze, described by firefighters as "serious", started on Friday morning at Skip-It containers in North Quay Road.
White smoke is continuing to billow hundreds of feet into the air, causing problems with visibility on the roads.
Residents and motorists have been advised by Public Health England to close their windows and doors.
Fire crews, which are being changed every six hours, remained at the site throughout Sunday night and the area is still cordoned off.
East Sussex Fire and Rescue Service (ESF&RS) is being supported by crews from neighbouring Surrey and West Sussex.
The fire service, Highways Agency and Sussex Police are due to hold talks to discuss whether cordons can be changed or lifted to allow greater access to the area.
Chief Fire Officer for ESF&RS Des Pritchard said he expected crews to be on the scene for some considerable time.
He said thousands of litres of water from the River Ouse were being poured on to the fire each hour, which was causing a lot of run-off.
"We are conscious about pollution in the river Ouse so we are working very closely with the Environment Agency about where the water goes," he said.
"We are dragging the waste out from the site into smaller piles and taking it away to another site about half a mile down the road.
"As far as we are aware it is all household waste so there are no particularly toxic or noxious chemicals within the waste pile - but it is unpleasant."
Public Health England said any smoke could be an irritant and people should either avoid being outdoors in the smoke or limit their exposure to it.
Respiratory symptoms could include coughing, wheezing, breathlessness, phlegm and chest pain. People affected should seek medical advice or call NHS 111.
The Environment Agency said its officers were monitoring the blaze and at this stage environmental impact was considered to be minimal.
The cause of the fire is not yet known. No-one has been injured.