Safety problems led to lab death

Emergency services could not save Mr Graham

The UK's leading medical research unit has pleaded guilty to breaching safety regulations which resulted in the death of an Edinburgh-based lab worker.

James Graham, 51, died from asphyxiation in October last year when liquid nitrogen was released at the Medical Research Council's facility at the city's Western General Hospital.

He was carrying out a routine task and had worked with the gas - used to freeze biological samples - for a decade.

MRC's safety improvements

Installation of a tank safety valve

Automatic filling of tanks with liquid nitrogen

Safety assessments

Better ventilation

New rule that staff must work in pairs

More staff safety training

Personal oxygen monitors

Clear warnings never to mute alarms

Appointment of a health and safety manager

The MRC admitted failing on a number of safety measures including inadequate ventilation, failing to ensure a warning alarm was switched on and failing to install a safety device to control a liquid nitrogen storage tank.

Edinburgh Sheriff Court heard on Tuesday that Mr Graham died in an incident where about 700 litres of liquid nitrogen leaked into a freezer room depleting the oxygen in the air.

Fiscal depute Liz Paton told sheriff Iain MacPhail, QC, that staff member Ruth Suffolk, 41, had gone into the room at around 0915GMT on 25 October.

She heard a hissing noise, saw a cloud of vapour and then found Mr Graham collapsed on the floor unconscious and frozen.

Raised alarm

Ms Suffolk immediately turned off the liquid nitrogen, which was streaming out of a hose attached to the wall, and raised the alarm.

She then collapsed on top of Mr Graham.

Staff member Stewart McKay dragged Ms Suffolk to the middle of the floor before leaving for fresh air. Colleague Agnes Gallagher then pulled her to safety.

It was fortuitous that more staff did not suffer the same fate as James Graham

Liz Paton, fiscal depute

It was Mr Graham's job to fill two storage vessels inside the unit from a tap controlling a 2,000 litre tank of liquid nitrogen outside the building connected by a metal hose.

He would then pump the chemical into flasks and various tanks, where human tissue samples used for research into diseases were kept frozen.

On the day of the tragedy he was filling the tanks from both internal storage vessels at the same time, an unapproved procedure, after switching off a safety alarm that measured oxygen levels.

Management aware

Because Mr Graham was at times exposed to low levels of oxygen during his work, the alarm would have gone off continuously while transferring the liquid nitrogen to the various containers.

It was known to the management that it was switched off during this dangerous task.

The monitor could not be seen from outside the room as it was blocked from view by freezers.

The lab had no windows apart from a panel in the door and the ventilation system was inadequate to cope with a major leak.

Gene therapy

There was also no safety valve on the external tank to automatically stop an excess of liquid nitrogen.

Mrs Paton said: "It was fortuitous that more staff did not suffer the same fate as James Graham."

The unit took part in Britain's first gene therapy trial for cystic fibrosis and conducts research in genetic therapy for incurable diseases including some forms of blindness.

Defending, Derek Batchelor, QC, said that the MRC had taken steps in all of its UK offices to improve safety.

MRC managers expressed their deepest sympathy for the victim's family, friends and the staff at the unit who had been shocked and distressed by the tragedy.

Sheriff MacPhail is to sentence MRC on Wednesday.