By Ian Findlay

An explosion that led to the deaths of a husband and wife in Dundee in 2000 was caused by natural gas leaking from a fractured cast iron main operated by Transco, an investigation into the incident has concluded.

The gas had escaped from the fractured pipe beneath a footpath and into a terraced house in the Happyhillock area of the city—where it was probably ignited by the tenant lighting a cigarette.

Fire triggered by the explosion claimed the lives of 67-year-old William Bailey and his 58-year-old wife Mary, who were in the next door house.

They died in hospital from the injuries they sustained.

Now a report issued by the Health and Safety Executive has recommended Transco renews similar cast iron mains across Dundee.

Over 1.2 kilometres of such mains in the area where the blast occurred were replaced with polyethylene mains immediately after the incident.

A programme to renew similar mains in the city is ongoing and the HSE is due to meet Transco soon to discuss its progress.

Other recommendations made by the Executive in their report include a call for Transco to improve its maintenance records and procedures.

The explosion at the centre of the probe happened at 23 Linfield Street on the morning of October 22, 2000.

The occupier of the house—a widow in her 60s—survived the explosion but was badly injured.

In its report the HSE says the gas main that fractured had been laid around 1967 and had broken “due to the stresses caused by the uneven settlement of the supporting soil over the sewer connections into the house combined with the stresses associated with a tapered service connection.”

There had been two previous fractures of four-inch cast iron mains in the same housing estate and in one case this had led to gas ingress and an evacuation of some houses.

It was also established by the investigation that the drainage had originally not been constructed to the correct standards when the housing was built for the then Dundee Corporation.

The report also states that on the evening of the day before the blast, a resident noticed a smell, probably of natural gas, near 21 Linfield Street.

“The smell continued to be noticed by various people up to the time of the incident the following morning; no one reported this either to the police or to Transco,” says the report.

Another of the recommendations in the report published yesterday is that Transco investigates the reasons why members of the public sometimes do not report gas escapes and to use this information to help improve public awareness and reduce the risks of known escapes going unreported.

The investigation was overseen by a special board—including an independent safety adviser—formed by the HSE because of public concern over previous gas incidents.

In June of 2001 the HSE sent a report to the procurator fiscal in Dundee in connection with the explosion.

In July the procurator fiscal’s office indicated that no charges would be laid against Transco and in December it was also indicated that a fatal accident inquiry would not be held into the incident.

Normally reports such as yesterday’s are not published until after any legal action has concluded, or after a decision that no action is to be taken.

The HSE’s specialised industries division head Dan Mitchell said yesterday, “HSE has taken a precautionary approach in agreeing an acceleration of the iron mains replacement programme with Transco in 2001 and continues discussion with Transco regarding measures that identify the highest risk main.”

In its findings, the HSE special board has noted that, as a result of developments in the economic and safety regulation of the gas distribution industry, a legislative change had been enacted which would require pipeline operators such as Transco to comply with a mains replacement programme agreed by the executive.

In a statement yesterday afternoon, Transco said it noted the decision.

“Transco has co-operated fully with all parties involved throughout the long investigation and believes that today’s decision is the correct one,” it continued.

“The company is, however, acutely aware of the distress felt by the family and friends of Mr and Mrs Bailey and again wishes to express its deep regret over this tragedy.

“In the last few years, Transco has accelerated its programme of replacing metal gas mains with durable and much more flexible polyethylene pipe.

“The HSE recently announced a new 30-year replacement programme for all iron mains within 30 metres of property and Transco, applying agreed criteria, is working its way through it.”

The HSE report says that, at the time of the blast in Linfield Street, Transco had a mains replacement scheme in place which was prioritised on the basis of risk.

HSE concluded from its investigation that Transco had complied with its prioritised replacement programme, which was fit for purpose, and that the main at 21-29 Linfield Street was not scheduled for replacement under this scheme.

The report also says there was some public concern that reports of gas escapes had been made to Transco before the incident.

No instances were, however, identified where Transco had failed to attend to a public reported gas escape and it was established that the company had fulfilled its legal duties in attending to reported leaks.

The investigation, however, identified a number of failings in Transco’s management systems:—

* Transco did not have a system for assessing local conditions that may have helped them identify the factors that may lead to fracture and gas ingress.

* Transco were found to have poor records and, although this was not a causal factor in this case, it could have implications for the identification of other mains at risk.

* While odorant levels appeared satisfactory, Transco did not assess the human factors involved in the non-reporting of gas escapes by the public which may have allowed it to more effectively target gas awareness campaigns.

The HSE board has also recommended that Transco take account of any “local factors” in its replacement policy; and that it should improve its maintenance records and procedures.