How safe are meth houses, really? And what's it like to go inside? Katy Gosset and Alison Ballance take the plunge and ask how much meth is too much when it comes to setting a national standard?

Meth houses have been in the headlines lately.

Housing New Zealand has been heavily criticised for using Ministry of Health guidelines designed for clandestine meth labs, to assess homes where the drug has merely been smoked.

And the Ministry of Health has just released new interim guidelines for properties where meth's been used

But debate continues as scientists try to pin down how much harm meth residues can cause.

Standards New Zealand is now working on a new national standard with a draft due out for public consultation in November.

The Science of... hears from the Ministry of Health, Massey University toxicologist, Nick Kim, and Environmental Risk Assessor, Jackie Wright.

And the team gets first hand experience of a meth house alongside the drug testing firm, MethSolutions.

Go to this episode on rnz.co.nz for more details