Dental toxic scare spreads

21:03, May 18 2014
Mobile dental clinic
TOOTHACHE: Canterbury's mobile dental clinics have been taken out of service for decontamination after unacceptable levels of formaldehyde were found in the ceiling tiles of one van.

A toxic chemical scare in a mobile dental clinic that has catered for thousands of Canterbury schoolchildren has caused alarm across New Zealand.

District health boards are pulling mobile dental vans off the road for urgent testing after formaldehyde levels three times national health standards were found in a Canterbury clinic.

However, because the standards are so conservative, experts say the risk to children was "negligible" and the risk to staff "very low".

Mobile dental clinic
TOOTHACHE: Canterbury's mobile dental clinics have been taken out of service for decontamination after unacceptable levels of formaldehyde were found in the ceiling tiles of one van.

For the past year, dental therapists from the clinic have suffered headaches, nausea, itchy eyes, runny noses, aggravated asthma and skin irritation.

The Press understands staff first complained about an acrid smell and chemical exposure symptoms in March 2013, just a month after the clinic first opened.

They feared the high potency smell was putting their patients - preschool and primary schoolchildren - at risk.


They tried airing out the clinic by opening the doors and windows and even brought in home remedies such as onions and cloves.

When the odour remained, the Canterbury District Health Board (CDHB) ordered a Chemsafety test that identified high levels of the hazardous chemical styrene in the air.

The clinic was taken out of service and a new ventilator system installed early last year.

The smell persisted and since then more than 1000 rural schoolchildren have been treated at the clinic.

It was not until the National Union of Public Employees (Nupe) became involved six weeks ago and "refused point-blank to allow staff to go back into the clinic on health and safety grounds", that the CDHB agreed to test it again, Nupe organiser Quentin Findlay said.

A broad spectrum test last month found formaldehyde levels in the ceiling tiles that were 200 per cent above Workplace Exposure Standards.

The CDHB called an urgent meeting with staff and offered health monitoring to those suffering from chemical exposure symptoms.

Its 22 mobile clinics were taken out of service to be tested and decontaminated.

In an information sheet handed to staff, the CDHB said it was "sorry to have caused understandable distress and concern".

The Ministry of Health, Worksafe NZ and New Zealand's DHBs who all use the same mobile clinic manufacturer were all notified.

Other DHBs have started testing their clinics and at least two have removed vans from service.

Worksafe NZ would be investigating how the contaminated tiles got into the van and CDHB would be investigating its own course of action to "highlight

what we could have or should have done differently", a spokesman said.

Nupe felt the CDHB's response to staff concerns had been "appalling".

Findlay, who had visited the clinic, said "you could smell it before you even got inside".

Staff members who raised concerns "were fobbed off and told there wasn't a problem", he said.

"They were treated with complete disdain and there has been a real loss of trust here. There was a legitimate problem and the CDHB basically had to be forced to do re-testing."

Last week, about 40 affected staff members attended a forum on the risks of exposure to formaldehyde with CDHB independent occupational physician Dr Andrew Hilliard.

Hilliard said the standards were conservative and any long-term risk to such minor level exposure was "very low".

He had no concern for the children that had visited the clinic because they would have only been inside for a short time.

Hamilton-based company Action Motor Bodies manufactured 108 mobile dental clinics for New Zealand DHBs in 2011 and 2012. A company representative said the chief executive was in Australia and could not be reached for comment.


Formaldehyde is a colourless, flammable and gaseous substance with a pungent smell. It is found in building materials and several household products, including carpets, upholstery and clothing. Exposure to high levels of the chemical can trigger nausea, watery or burning eyes, respiratory irritation, difficulty breathing, headaches and asthma attacks. The acute effects of short-term exposure would normally cease within an hour. However, long-term exposure to high concentrations of the chemical could cause chronic health effects and in rare cases even cancer. 

The Press