Rotorua's whiff can be deadly

Contractors in Rotorua are dicing with death every time they dig a hole, says Rotorua District Council inspector Peter Brownbridge.

He said he was surprised more contractors, like plumbers and drainlayers, hadn't succumbed to the toxic hydrogen sulphide that seeps out from under the ground.

"I still see some sites that make me wonder why there haven't been more deaths."

Mr Brownbridge, a council geothermal inspector, said some work practices were just tempting fate and there was a lot of complacency among those working around Rotorua.

Out-of-town workers who "sort of know about hydrogen sulphide but don't know the dangers" were the worst.

The colourless toxic gas has been attributed to at least 11 deaths in Rotorua over the past few decades.

Mr Brownbridge said it was not uncommon for workers to move the gas detector away from the site because the alarm was "too noisy".

While none had been killed over recent years, several had been "knocked out" by the gas.

Mr Brownbridge said he didn't want to scare the public, but there were certainly dangers around the gas, with the hazard level depending on the duration of exposure and its concentration.

Levels of hydrogen sulphide in the air are being constantly monitored. People who noticed "funny smells" could call the council to check on the levels in their buildings.

Places had been evacuated and some buildings shut down while the source of the gas was found.

Rotorua's geothermal gases were also linked with higher than average asthma rates in a 2003 study.

This found that between 1991 and 2001 that people living in six Rotorua suburbs were admitted to hospital with asthma five to 10 times more often than those living in other suburbs.

Deaths linked to geothermal activity in Rotorua:

* In 1946 one person died in a spa.

* In 1948 one person was killed and one overcome by fumes during sewer pipe maintenance.

* In 1954 one person died and four were overcome by fumes upon entering a septic tank.

* The same year another person was overcome by fumes in a hot pool and drowned.

* Also in 1954 one person died while digging a sump hole.

* In 1962 two died and their deaths were blamed on a leaking pipe in the groundwater-fed heating system.

* Also in 1962 a person died in a confined room.

* In 1987 two died after a faulty shower tray let gas into a motel room at night.

* In 2000 a person died but the source of the hydrogen sulphide was unclear.

- NZPA