I was shocked to read such a sensationalist piece on the supposed hazards of illegal meth labs (26 April, p 32). Anyone with even a little chemical knowledge will know that the chemicals referred to are unlikely to cause problems weeks or months after the drug lab operators have left.
Hydrogen chloride gas, for example, (readily available in solution from hardware stores) disperses rapidly and would have caused choking even at low concentrations. Any residual drugs or drug "precursors" would have been found and disposed of or reported.