A group of councils and "green waste" companies has succeeded in persuading an environmental regulator to block householders' access to a herbicide for lawn weeds, because it is disrupting the compost trade.
The Environmental Risk Management Authority (Erma) has ordered retail packs of weedkillers containing the herbicide clopyralid to be taken off the market from August 19 next year.
Clopyralid is the active ingredient in a range of herbicides approved 23 years ago for the control of broadleaf weeds, such as dandelions, clover and thistles, in suburban lawns, sports turf and hay crops.
The Business Council for Sustainable Development asked for the ban - but the contact person for its application was George Fietje, general manager of the compost company Living Earth, which has long campaigned against the herbicide.
Concerns were first raised in the late 1990s and Living Earth formally complained in 2002 that grass clippings containing spray were contaminating its compost.
But that bid for an Erma re-assessment application was withdrawn a year later, apparently after the company was told future law changes would give Erma greater flexibility to set conditions on the use of chemicals.
The sustainable development council made a new application yesterday.
"Current use on both domestic and commercial turf continues to give rise to residues in the green waste that severely affect plants grown in such compost," it told Erma.
In 2004, Living Earth successfully lobbied Auckland, Waitakere and Christchurch councils with interests in recycling green waste, and the Environment Ministry, for cash to take a new case to Erma to have householders banned from access to the herbicide.
It estimated the bid would cost $18,000.
Companies and councils selling compost - made with green waste recycled from suburban lawns and gardens - met buyer resistance when the compost killed sensitive garden seedlings such as tomatoes, peas and beans.
Turf managers at sports fields found the herbicide particularly effective for killing prickly weeds - such as the lawn pest Onehunga weed - and clover, and because of its low toxicity, the fields could quickly be returned to use.