New reports reveal that residents living above Nelson's port could be exposed to potentially dangerous levels of a toxic gas.
The chemical methyl bromide is used to fumigate export grade timber, and some residents have long argued it led to a group of Nelson port workers dying from motor neurone disease.
New reports show that in the worst case scenario, residents would face gas levels twice the workplace safety standard.
The reports have been released by the Environment Court in a case involving fumigation company Genera.
Claire Gulman from Campaign Against Toxic Spray says such findings should spark more protest action.
Genera, says it is seeking to introduce a system that will capture all the gas. Spokesperson Alan Perry says the reports are based on theory, not scientific fact.