Rumours persist in Christchurch that asbestos inhaled from earthquake dust and debris will cause death and disease. DEIDRE MUSSEN investigates the risks.

A photograph capturing Christchurch on February 22 last year shows a thick pall of dust cloaking the city. Within 24 hours, health officials were out spreading warnings of asbestos risks.

Since then, the city's asbestos management has been under the spotlight as numerous buildings are demolished and rubble mountains created.

Fears have been fanned by a handful of horror stories, the latest an abandoned demolition dump in Sydenham. In May, a protest by residents over proposed asbestos dumping at Burwood Resource Recovery Centre forced the Christchurch City Council to send it instead to Kate Valley landfill in North Canterbury.

So what is the asbestos health risk to Christchurch residents post-quake?

Extremely low, according to Canterbury medical officer of health Dr Alistair Humphrey, who is eager to dispel community concerns.

"The question is, 'could people have been exposed at the time to asbestos?' The evidence suggests not."

Other asbestos experts agree but admit they won't know for decades.

Typically, people need heavy exposure to asbestos fibres and usually for a long time, but there is a long time lag between exposure and becoming sick.

This is borne out by New Zealand's two asbestos registers, which began 20 years ago and gather data on exposure and disease. Of the 1246 people registered with asbestos-related diseases since 1992, 99 per cent were caused by exposure many years earlier, before people understood its dangers.

"It's probably people who worked without any protection," Humphrey says.

More than two-thirds worked in the building industry, including plumbers, fitters, laggers, carpenters, builders and electricians.

Most of the rest were asbestos processors or sprayers, although a few breathed in fibres from their partners' asbestos-laden clothes or hair.

Asbestos, a known carcinogen, can cause mesothelioma, a rare fatal cancer of the lining of lungs or abdominal cavity, lung cancer, asbestosis or scarring of lung tissue, and pleural plaques.

Humphrey says there has been a background level of asbestos in our lives since it began being imported into New Zealand in the 1920s in brake linings and clutch pads.

It was commonly used from the 1940s to the 1980s in roofing, wall and ceiling claddings, insulating boilers and pipes, and as a fire retardant on structural steelwork.

"You and I will probably have thousands of asbestos fibres in our lungs but will never get sick from them."

He says brief possible exposure to asbestos by people inhaling dust near collapsing buildings or during early rescue attempts was extremely unlikely to be enough to cause disease.

Plus, asbestos monitoring since the February 22 quake has failed to detect any unsafe levels and many buildings that fell were built in the pre- asbestos era. Controls on work safety in the red zone were quickly instituted, including strict precautions for rescue workers and those removing asbestos.

A proposed new study into asbestos in New Zealand may shed more light on the issue.

Massey University's Centre for Public Health Research associate director, Associate Professor Barry Borman, says his study will link asbestos exposure records with mortality, hospitalisation databases and the New Zealand Cancer Register.

"Therefore, we will be able to see what causes of death, hospitalisation, or cancer that these people have experienced since the register started in the early 1990s," he says.

The asbestos registers are an incomplete record of asbestos-related disease cases because notification is voluntary, whereas the cancer register is compulsory.

According to it, 1024 cases of mesothelioma were diagnosed in the 15 years to 2009.

ACC's Dr John Monigatti, who has reviewed all claims for compensation for asbestos-related disease for the past 15 years, says it is unlikely Cantabrians will suffer from asbestos-related diseases from the earthquake but he is keen to see the proposed study's results.

"It is feasible and no one will know for 30 to 40 years that there could be a peak."

He says lung cancer and mesothelioma may require only short periods of exposure over a few weeks but in high levels.

Those with asbestos- related diseases can get lump sum payouts from ACC, with $57 million paid out in the past six years to 701 people, the vast majority for mesothelioma. However, only about half those diagnosed with mesothelioma gain lump sum compensation, which raises concerns people are not seeking compensation they are entitled to.

The latest cancer statistics show 91 people registered as being diagnosed with mesothelioma in 2009, including 76 men and 15 women. That year, 101 people died of it, while only 51 people got compensation.

One of New Zealand's leading asbestos researchers, Professor Bill Glass, says most asbestos-related diseases are dose-related, although this may be less true with mesothelioma.

"The length of time of exposure doesn't have to be long but the quantity of asbestos over that time does have to be high."

He has led the asbestos medical panel for 20 years and has intimate knowledge of the hundreds of people who have suffered the consequences of asbestos.

The time lag between exposure to asbestos and diagnosis with mesothelioma varies from 12 to 74 years for the register's 227 cases, with an average time of 45 years.

Post-February 22, there has been a surge in notifications of asbestos exposure, according to the Ministry of Business, Innovation and Employment's Labour Group, which replaced the Labour Department.

Last year, 61 Cantabrians put their names on the asbestos exposure register, 46 more than the previous year and more than double the region's annual average of 25 people for the previous four years. That increase has slowed this year.

The New Zealand Demolition and Asbestos Association says that is no surprise. In the past eight months, it has had 15 new applications by contractors wanting to do asbestos removal in Christchurch, says president Diana Stil.

Only those with a certificate of competency can legally remove friable, or easily crumbled, asbestos, which is more likely to release fibres into the air if disturbed.

It has been a challenging environment; some earthquake-stricken buildings were unsafe to enter to remove asbestos, forcing "dirty demolitions", Stil says.

"Also, there have been buildings where it was assumed prior to the earthquake that a clean-out had been done, then asbestos has been found after the demolition."

The association's 200-plus page New Zealand Guidelines for the Management and Removal of Asbestos was published only weeks after February's earthquake, after gaining endorsement by the then Labour Department.

She says the vast majority of operators have been very careful in managing asbestos when demolishing earthquake-damaged buildings.

"But you are always going to get the odd rogue.

"The most important thing is getting the public aware. There is a lot of fear about asbestos."

The Labour Group's Christchurch service manager, Margaret Radford, agrees, saying the community wrongly believes asbestos risks from the earthquake are high.

She too is eager to change that. "I do think it is an emotive subject."

Most contractors have adhered to asbestos regulations, with only 22 "events" since the quake until mid-June, despite thousands of hours in earthquake- related work, she says.

"The departmental perspective is asbestos has been handled extremely well since the beginning, though maybe not in the first few days only."

Since February 22, the ministry has stepped up monitoring health and safety for the Christchurch recovery.

Post-earthquake, the ministry has been notified of about 320 "hazardous" demolition sites because of asbestos removal.

New Zealand is not the first country to face issues with asbestos risks from earthquakes.

The 1989 San Francisco earthquake prompted the United States Environmental Protection Agency to develop its first guidelines two years later for catastrophic emergency situations involving asbestos.

According to the International Ban Asbestos Secretariat, a rubble collector in Japan became the first to gain worker's compensation in 2009 for developing mesothelioma after being exposed to asbestos while cleaning up debris after the 1995 Kobe earthquake.

On that earthquake's 15th anniversary in 2010, the former co-director of America's Mount Sinai School of Medicine's centre for occupational and environmental health, Dr Stephen Levin, addressed a conference in Japan on lessons about asbestos risks from Kobe and the World Trade Center disaster.

Before he died in February, Levin helped to lead a study of more than 27,000 responders and recovery workers for 9/11, a group set to become one of the most examined groups for health impacts of an international disaster.

Researchers say the huge plume of dust and smoke that spewed into the air when the twin towers collapsed after the terrorist attack on September 11, 2001, contained dangerous levels of asbestos .

Humphrey says it is unhelpful to compare to Christchurch's earthquakes to the World Trade Center because the disasters are so different.

Regardless, the message from health experts is clear: fears over earthquake-related asbestos have been blown way out of proportion.

In fact, a far greater health risk is that smoking levels have risen in Canterbury since the earthquake, despite reducing nationwide.

Smoking is far more likely to cause premature deaths than misplaced anxiety over post-earthquake asbestos, Humphrey says.

- © Fairfax NZ News

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