The Nelson and Tasman councils are working together to develop a set of procedures for dealing with clandestine drug production labs police alert them to.

Nelson's environmental inspections manager Stephen Lawrence said in a report to the city council that a worrying feature was that manufacturers were switching from using "static sites" in the production of methamphetamines, which used highly toxic and explosive chemicals, to temporary facilities like motels and even producing from the boot of a car.

Tasman district environmental health co-ordinator Graham Caradus said an expert speaker at a recent environmental health conference warned of the increase in "shake and bake" method, in which small-scale methamphetamine manufacturing is done in soda bottles. These "one-pots" are described as "incredibly toxic and volatile".

In November 2010, Nelson police uncovered a suspected clandestine methamphetamine laboratory in a motel, which led to the arrest of a 32-year-old Nelson woman and two Nelson men, aged 32 and 37, who were charged with manufacturing methamphetamine.

That year police uncovered five P labs in the Tasman police district. They were in Nelson, Dovedale and Wakefield, while the other two were in Blenheim and on the West Coast.

Mr Caradus said environmental health groups from councils around the top of the South Island met regularly to "kick around technical stuff" in an effort to get compatible standards in environmental monitoring, and labs for manufacturing illegal drugs was just one area they were working on.

He said they were using Department of Health guidelines in developing procedures.

Mr Caradus said P labs ranged in their degree of development from "full-blown active labs" in which drugs were being made to premises in which equipment was evident, but the chemicals were untouched in sealed containers.

"If we think there's been a lab to any extent we [local authorities] then put a cleansing order on the property that requires the property owner to clean it to necessary standards."

Mr Caradus said an assessment of what needed to be cleaned could cost several thousand dollars even before cleaners moved in. The cost was covered by the property owner, and in most cases P labs were set up in rental homes.

He was not aware of any cases in Nelson or Tasman like others around the country, where premises had to be stripped out completely, including all soft furnishings.

Mr Caradus could not say if the problem was getting worse, except that 10 or 15 years ago they had not heard of the problem.

"I don't know if the problem is increasing or the police are getting better at catching these people."

Despite the risks P labs presented, he said it was important to keep the risk in perspective. Stored fuel in private garages could be just as volatile.

- © Fairfax NZ News