WORK at a chemical plant rocked by an explosion is still suspended two months after the blast.

Production at the Terra Nitrogen site on Teesside was halted by safety officials after the incident, which took place at the start of June.

Two workers were treated for minor cuts and shock after the explosion at the complex in Billingham, which employs 250 people.

An investigation by the Health and Safety Executive (HSE) and Environment Agency was launched to discover the cause.

It was initially thought the blast and fire, which could be heard and seen up to 20 miles away, involved mixed gases and started in a pipe.

HSE investigators are still monitoring the situation and have so far refused to give the US company approval to resume production.

An HSE spokeswoman said last night: "Work has not yet started at Terra Nitrogen and pre-production checks are still being carried out."

In the wake of the explosion, company bosses insisted the blast did not present a danger to nearby residents or give rise to public health issues.

Stockton North MP Frank Cook, whose constituency the site is in, has called on the company to keep him fully informed of develop-ments.

It was thought that a fire involving mixed gases - including hydrogen, nitrogen and ammonia - caused the explosion.

The company is the UK's largest manufacturer and marketer of ammonia, nitric acid and carbon dioxide.

In the aftermath of the blast, it was said the explosion led to a nationwide shortage of carbon dioxide, which is used to make soft drinks fizzy.

Companies such as the Irish based C&C group, which makes Magners cider, was among the companies most badly affected.

It has had to import the gas from eastern Europe because of the shortage.

Terra Nitrogen had hoped to have the plant working again by the end of July, but it is still not known when production will resume.