People are being asked not to go into the water near Auckland's Manukau Harbour after a chemical spill yesterday.
About 5000 litres of methyl methacrylate, which is used in the manufacture of plastics and adhesives, spilled from storage at a specialist chemical business on Industrial Road yesterday.
It has since gone into a stormwater drain, and into the Manukau Harbour.
Auckland Council’s manager of environmental health, Mervyn Chetty, said warning signs have been put up in the area, and the council's Safeswim website is also telling people not to go into the water five kilometres from the spill – which covers Mangere Bridge, Taumanu East, Taumanu Central, Taumanu West and Onehunga.
Late last night Auckland Council advised that staff, including environmental health and pollution experts, had been at the scene since it was reported, working with Fire and Emergency New Zealand and consulting with Auckland Regional Public Health.
Fire and Emergency told 1 NEWS the incident happened about 11.20am and crews that were still on scene assisting in the clean-up as of 10pm.
The chemical is considered to have a low toxicity, but it may cause nasal, eye, skin or respiratory irritation, as well as headaches.
As a precautionary approach, Auckland Regional Public Health Service medical officer of health Dr David Sinclair asked anyone who could smell the chemical, which has an acrid and fruity odour, to close their doors and windows.
"To avoid experiencing the unpleasant smells and any potential irritation, we advise people in the wider Penrose and Onehunga area to consider closing doors and windows," he said.
"If you work in this industrial zone you may also need to keep doors and windows closed tomorrow too."
Anyone with concerns is urged to contact Healthline on 0800 611 116 for advice.
Auckland Council is investigating how the spill happened.