Two people have been treated for burns after an explosion and fire at a chemicals factory in Irvine.
Casualties were taken to hospital from the chemical plant
The incident at the GlaxoSmithKline site in Shewalton Road occurred at about 0700 GMT.
Two people, aged 45 and 51, were taken to Crosshouse Hospital, in Kilmarnock, and then transferred to a hospital in Glasgow suffering from burns.
Two others were treated for shock. Police said 20 people were in the factory at the time.
The explosion happened in the plant's Actives facility, where raw chemicals used in the production of malaria and HIV drugs are treated.
One side of the factory building is thought have been blown off in the blast.
The explosion started a fire which was put out by the plant's sprinkler system.
GlaxoSmithKline said the facility had been closed down as a result of the blast.
An explosion and fire occurred in a building preparing chemicals for the production of penicillin at the same plant in 1999.
The company was fined £20,000 after that incident.
Plant director Jim McPherson said: "Two staff who suffered some shock have both gone home now.
"Two others who have received some burns, both of those individuals have been transferred to Glasgow Royal Infirmary.
"Our message in the first instance should be that we as GlaxoSmithKline, and me as the site director, take seriously our responsibilities - safety is our first priority."
An investigation into the cause of the blast is under way
Pharmaceuticals are produced at another facility on the same site, which was not affected by the blast.
Three ambulances were sent to the scene and police set up a cordon and closed roads.
Operations at the plant will not restart until the cause of the blast has been established.
A spokeswoman for Strathclyde Police said: "The emergency services are at the site and there will be a full investigation into the cause of the explosion."
A spokeswoman for the Scottish Environment Protection Agency (Sepa) said its officers were on site and liaising with the Health & Safety Executive.
She added: "The cause of the explosion is, as yet, unknown and SEPA is at present not aware of any environmental impact, but the investigation is still under way."