A major fire at a recycling centre which has been burning for three days is believed to have been arson.
Fire crews used diggers to remove mounds of burning rubbish from inside the Oxigen plant in the Merrywell industrial estate in Ballymount, Dublin before dousing the flames.
Strong winds have helped reduce the risk of pollution and health problems for people and businesses in the area.
However, tonight An Post have confirmed that the nearby Marywell parcel depot has been forced to close temporarily as a result of heavy smoke from the fire.
Thousands of parcels are handled at the Marywell depot so customers can expect disruption to service for at least 24 hours.
It is understood investigations centre on the inferno being started deliberately after another fire was reported at a carpet centre in the same industrial estate on Saturday night.
The fire, although contained and under control, is expected to burn for a number of days, possibly until Thursday.
The Environmental Protection Agency (EPA) has had inspectors on site everyday since the blaze broke out and said that there has been a significant reduction in smoke levels today.
But a spokeswoman warned: "In Dublin, smoke from Ballymount fire may cause poor air quality in local areas for the rest of today."
Three units of the Dublin Fire Brigade remained on site to douse flames and ensure the fire did not spread.
Tonnes of burnt recycling material - standard domestic plastic, paper and packaging and bales of paper and cardboard collected from businesses - were removed from the storage and processing building at the Oxigen plant.
Fires reignited in some mounds of rubbish even after being soaked. Fire crews on the scene said that was to be expected due to the sheer quantity of smouldering and hot material.
None of the EPA's air quality monitoring stations around Dublin recorded any pollution issues.
All stations - Balbriggan, Blanchardstown, Coleraine Street in the north inner city, Dun Laoghaire, Rathmines, Swords, Tallaght, which only tests for sulphur dioxide, Winetavern Street in the south inner city - have good quality, tests showed.
The monitors record data on particles and gases such as nitrogen oxide, sulphur dioxide and carbon monoxide.
The EPA has received 65 complaints over the lifetime of the Merrywell Oxigen facility July 2006, mainly relating to odour.
The EPA warned people with lung problems and heart problems and older people to reduce strenuous physical activity, particularly outdoors, and people with asthma may need an inhaler more often. It also urged anyone experiencing discomfort such as sore eyes, cough or sore throat to reduce activity, particularly outdoors.
The fire will be investigating by gardai, the fire service and the EPA.
Oxigen said it had recently stopped receiving hazardous waste at the site although concerns were raised about pollutants and toxins from burning plastics.
Asbestos was among the materials stored at the recycling plant but it was removed before it could catch fire.
The watchdog was also briefed on materials which were being stored and processed at the plant.
The Asthma Society of Ireland (ASI) said it believed the weather played a part in reducing the air pollution
In a statement, Oxigen said: "As the fire is yet to be totally extinguished, the investigation into the cause is yet to commence."
The company employs more than 120 people at the site and up to 75 jobs are directly involved or linked to processing recyclable waste.
It said management were actively working to protect as many jobs as possible by relocating staff across other depots and areas of the business. It will be the end of the week before it is known how many jobs could be at risk.
Oxigen also said domestic and commercial collection services remain uninterrupted.