Toxic 'slug' afloat on the Waikato

By SCOTT MacLEOD and ELIZABETH BINNING

A poisonous pool of chemicals from a truck explosion is floating down the Waikato River and forcing towns and businesses to shut off their water supplies.

Authorities moved fast to warn major water users of the chemical spill, but private users who draw amounts too small to need council approval have not been told to switch off.

Watercare Services, which supplies Auckland's water, shut its controversial Waikato treatment plant at 8am yesterday for the rest of the week.

Huntly, Ngaruawahia, Te Kauwhata and Taupiri also stopped taking drinking water from the river. The towns are relying on reservoirs.

The chemicals were on a truck laden with eight tonnes of chemicals that burst into flames in Hamilton at 8pm on Monday, apparently when sparks flew off its brakes.

A string of explosions rocked houses 2km away.

The driver of a courier van saw smoke coming from the back trailer and radioed the truck driver.

The truck driver pulled over and called firefighters. He then detached the two trailer units when he realised they were about to explode.

The trailers were carrying at least eight chemicals, the most dangerous of which were toluene and an organophosphate.

Eight fire trucks were called to the blaze, at the intersection of Cobham Drive and Normandy Ave. Some of the chemicals burned off.

Small dams were set up to contain the rest, but they burst and pink goo seeped into two streams, killing eels and small fish.

It then formed a pool, or "slug", in the Waikato River and started drifting north.

Firefighters cleared charred debris yesterday and workers resealed the heat-damaged road.

Environment Waikato water scientist Bill Vant said one "silver lining" was that the chemicals included a strong dye that had stained the chemicals pink. Council officers were able to track the slug.

Major water users were told of the slug, but dozens of smaller users do not need a permit, and are therefore not on council records.

Mr Vant said those users, including farmers, "would be wise to switch off" as the slug passed.

Environment Waikato staff hoped private users would learn of the slug through media reports.

Council workers believe some of the chemicals have been heavily diluted by the river.

They believe the water should be safe except near the slug.

Two of the biggest water users on the river are the Affco freezing works at Horotiu and the NZMP milk powder and cream plant at Te Rapa. Affco said the plant stopped drawing water from the river as the slug passed and NZMP said the water was used for cooling rather than mixing with food.

The truck belongs to the Chemcourier division of Mainfreight, which has started an internal inquiry.

Further reading
nzherald.co.nz/environment