The Health and Safety Authority is investigating the spillage of 150 gallons of highly toxic acid in Mulhuddart in west Dublin yesterday.
Seventeen people were treated in hospital when a lorry shed more than 10 barrels of the toxic chemical, nitric acid, at the Church Road roundabout shortly after 9 a.m.
Residents were told to stay indoors until lunchtime.
Nitric acid is corrosive and can cause severe burns, while its vapours are corrosive to the respiratory tract. In severe cases inhalation can cause fatal pulmonary oedema.
The Health and Safety Authority said last night it would be investigating whether the regulations governing the transportation of dangerous goods were complied with in yesterday's incident.
A spokesman for the Department of Enterprise, Trade and Employment said it would consider making changes to the regulations if that was deemed necessary following the investigation.
Mr Stephen O'Driscoll, an electrician who was driving near the roundabout at the time of the spill yesterday, told The Irish Times that the truck was trying to take the roundabout when the barrels came flying off the side. The truck was a curtain-sided container.
"One of them split and went all over the car behind. It looked from where I was that the paint on the car was starting to blister up. We were blessed there weren't loads of pedestrians or people on bikes around the place."
He said there was a sense of panic as fumes started to fill the air immediately.
The acid was being transported by the Chemco company. A spokeswoman for Chemco said it would not be issuing any statement on the matter until this morning "at the earliest".
Three people were removed by ambulance to James Connolly Memorial Hospital. One woman was treated for burns to her arm. A further 14 people presented at the hospital. All 17 were discharged following minor treatment.
Four appliances from the Dublin fire brigade attended the scene along with gardaí from Blanchardstown, officials from Fingal County Council and an inspector from the Health and Safety Authority. Gardaí wearing protective masks were yesterday directing traffic away from the village.
Mr Joe Brennan, mobilisation officer with the fire brigade, said 24 personnel attended the scene wearing liquid-tight chemical incident suits. A cordon was thrown around the area while the nearby Lady's Well National School was told to bring all its pupils indoors and to close all doors and windows until the scene was made safe.
Ms Margaret Howard of Fingal County Council said the acid was neutralised with caustic soda and sand was spread to soak it up, before being swept into bags and removed to the nearby Fingal Roads Department depot in Coolmine.
The area was declared safe and traffic was readmitted shortly after 5 p.m.
Mr Stephen McGarry, an inspector with the Health and Safety Authority, said he would investigate whether the regulations governing the transportation of dangerous goods were complied with in yesterday's incident. "Curtain-sided vehicles can be used if the load is properly secured and is safely and securely in place."
Asked whether the HSA had enough inspectors to ensure regulations were adhered to, he said the HSA "frequently comes across breaches" of the regulations.
"We could always do more with more resources. The authority is operating as best they can with the resources assigned to them," Mr McGarry added.