The Dunedin City Council has introduced a new step in its consent processes for many pre-1945 houses after an analysis found lead paint in the surrounding soil could be seven times higher than contamination standards allow.
The council said it had to implement government regulations, including the Resource Management Act.
And it said the new processes would only apply in limited incidents.
"In this case, if we become aware a project is likely to disturb potentially contaminated ground, we are required to take appropriate steps," a council spokesman said.
"There is a public health discussion to be had about the hundreds or potentially thousands of other homes in Dunedin that are presumed to be contaminated by the historical use of lead-based paint and are now considered a threat to human health.
"Those properties are not being tested or remediated, and families continue to be at risk of exposure.
"Children, particularly pre-schoolers and those families with vegetable gardens, are at greater risk and there is no current regulatory pathway to address persistent lead residue on those residents."
The council spokesman said the issue was not unique to Dunedin, or New Zealand.
He referred questions about public health to Health New Zealand Te Whatu Ora.
(A Health New Zealand spokeswoman said yesterday the government agency would respond next week.)
The council, following advice from the Ministry for the Environment, commissioned construction consultants Stantec to review lead contamination around residential buildings last year.
Stantec’s report, published on the council website this week, said "white lead" was phased out of paint in New Zealand from 1945 and its use was banned in 1979.
Chronic exposure to the substance could cause neurological, cardiovascular, haematological, immunological, reproductive, and developmental effects, especially on young children, it said.
There was no evidence pre-1945 brick houses faced the same issue, but soil within 2m of a pre-1945 weatherboard or roughcast-clad house should be tested for lead contamination, it said.
Stantec’s analysis found 95% of pre-1940s houses had soil lead concentrations above the contamination standard for residential land use.
The average soil lead concentrations found around houses built before 1945 surpassed residential land use standards "by a factor of seven".
Stantec said for some household gardens or where community gardens were proposed, soil should be tested against the contamination standards.
In a letter to stakeholders, obtained by the Otago Daily Times, council resource consent manager Alan Worthington said for all applications for resource consent for subdivision or land use, the council would be considering the potential for soil contamination from lead paint.
The planning check of building consent applications would also consider the potential presence of lead from paint.
"Where the site development relates to a property where there currently is, or previously has been, a pre-1945 building, it is more likely than not the site will be considered a possible Hail [Hazardous Activities and Industries List] site under Hail category I," he said.
The council website said only a small number of properties each year would be affected by the change.
"For everybody else, nothing changes."
TGC director George Hercus disagreed.
About 45% of the homes in Dunedin were built before 1941, Mr Hercus said.
Consent processing times had increased about 50% due to the change and the cost of a development had increased between $20,000 and $30,000.
"So, for example, in a four-home development, the cost to the end customer has increased by $5000 to $7000 per home."
