INSPECTORS will today start an investigation after a chemical poisoning incident in the region.

Nine firefighters were among the 19 taken to hospital after a worker was overcome by fumes on Teesside.

The 28-year-old had been cleaning a tanker at chemical company Bulkhaul, which contained the potentially-fatal herbicide paraquat.

Colleagues at the chemical transport firm rushed to help him but were also affected.

Police, fire crews and ambulance personnel attended the scene, at about 11am Saturday, at Middlesbrough's Riverside Industrial Estate.

Grangetown fire station manager Tony Churchill said 40 firefighters, seven fire engines, an emergency tender and an environmental protection unit were involved in the rescue operation.

A spokeswoman for the Health and Safety Executive said last night: "We have been made aware of the incident and an inspector will attend the scene on Monday to start an investigation.

"It will depend on the damage and the location of the incident whether the site should be closed for our investigations to commence."

Other victims of the fumes were taken to James Cook University Hospital, and later released.

The Bulkhaul worker who fell into the tank was yesterday being monitored in intensive care and will be assessed by doctors today.

Accident and emergency registrar Patrick Dissman said: "If ingested in large quantities, it can lead to serious lung and liver damage and even death.

"If it is inhaled or comes in contact with the skin, the symptoms are similar to a chemical burn, causing blistering, irritation, sore throat and coughing."

Cleveland Police spokesman Sergeant Neil Walker said of the Bulkhaul worker: "It would appear there was a little more paraquat left in the container than he appreciated and he was overcome by the fumes - whereupon several of his colleagues entered the tank to go to his aid. They too were overcome.

"The fire brigade brought with them a decontamination shower unit and showered everybody off, then the 19 people affected were taken to hospital.

"Everybody taken to hospital had suffered inhalation injuries. Thankfully, though, these injuries were not serious."

The police set up a cordon surrounding the plant, Sgt Walker said.

He added: "The incident is being treated as an industrial accident and the Health and Safety executive has been informed.

"There was no threat to any homeowners. The plant is right in the middle of an industrial estate."

Paraquat is one of the most widely-used herbicides and is used to control weeds in a wide variety of crops.