Horizons Regional Council received complaints on Friday night and Saturday, and sent consents monitoring officer Robert Rose to Wanganui on Friday afternoon. He prowled the Balgownie Ave area and visited the meatworks.
An Affco manager admitted that their rendering plant was the source of the smell, but plant manager Troy Lambly was not available for comment yesterday.
The rendering plant processes unsaleable animal parts from Wanganui and elsewhere into meat and bone meal, but a mechanical problem had shut it down. By the time it got going again, it was processing offal and other animal parts that had become smelly.
In the 1990s there were a lot of odour problems from the rendering plant, and a working party was set up to address them. After an expensive upgrade Affco regained consent to discharge to air, provided there were no "objectionable odours".
Mr Mitchell-Anyon was a member of the working party. He said the animal parts were supposed to be washed with acid to prevent bacteria growth and bad smells.
"Anything not up to spec had to be turned around and sent back to the supplier, and not processed. Even tipping that into their hopper they would have broken their resource consent."
He said most of the product processed came from other towns, where they wouldn't get resource consent to build a plant.
"The risk of failure is so high. For some reason Wanganui has the pleasure of accepting everyone else's waste."
Mr Rose said the wind was gusty on Friday, and the smell was there one minute and gone the next. "But we did detect an odour that we deemed objectionable."
That was a resource consent infringement, incurring a fine of probably $750, and a requirement to stop making such smells.