Rotting animal skins, once an export earner, are forcing staff at Hawke's Bay's Omarunui Landfill to wear masks to guard against toxic fumes.
Hawke's Bay Regional Council has upheld odour complaints and issued the landfill with an infringement notice, a report to the landfill committee said.
The Meat Industry Association says low grade hides and skins are uneconomic to process, so instead are being sent to landfill.
"Due to global market conditions, it can be uneconomic to process certain grades of cattle hides and sheep skins," chief executive of the Meat Industry Association Sirma Karapeeva said.
"As a result they are composted or at times deposited in landfills."
The Hawke's Bay inter-council Omarunui Refuse Landfill Joint Committee Meeting was told Friday last week that an increased number of pelts was first noticed 18 months ago.
"When we get these large volumes it is difficult to handle them, because they are best dealt with mixing in with the general waste," Hastings District Council waste and data services manager Martin Jarvis said.
"If the proportion isn't right you end up with difficulties managing to compact that waste down.
"Also the odour can be quite extreme in some of those loads. Quite putrid.
"So these loads we always like to cover immediately and it is difficult to if you don't have other waste coming in to be able to cover them.
"In response to this we actually asked that pelts and skins don't come in after 2pm."
He said the problem first arose when Napier composting business BioRich restricted the amount of animal waste it took.
The increased level of animal products is credited with the 22 per cent higher tonnage received by the landfill to March 31, compared with the same period for the previous year.
Landfill expenditure on the Emissions Trading Scheme is $1.2 million above budget due to higher costs associated with the higher tonnage.
According to Statistics New Zealand, the Hawke's Bay's sheep population dropped by 346,000 sheep last year.
This would have led to a spike in processing numbers for meatworks.
Landfill staff say many of the sheep skins still have a good amount of wool on them.
Jarvis said staff undergo tests on how well their masks fit and are wearing gas monitors to detect harmful gases.
"If you get close to some of the vehicles that are coming in it is reading an elevated level.
"So we know it is coming in on these loads and these loads are mainly the pelts, skins and the chromium waste coming from tanneries."
Jarvis said landfill machinery, currently on order, will have cabs fitted with filters to keep out toxic gases such as hydrogen sulphide.
He said costs associated with the toxic emission's are why skins, pelts and other hydrogen sulphide-contaminated waste have been given their own charging category from next month, with fees rising from $180 to $300 per tonne.
The central government levy for all landfill waste is also rising next month, from $10 per tonne to $20 per tonne.
Further annual rises will bring the government levy to $60 per tonne in 2024.