‘No stone will be left unturned’: authorities vow ‘big investigations’ as Derrimut chemical factory fire smoulders

Warnings to avoid nearby waterways as EPA says same Melbourne factory was issued notices after previous fire

• Follow our Australia news live blog for latest updates
• Get our morning and afternoon news emails, free app or daily news podcast

Victoria's environmental regulator has warned residents in Melbourne's west to avoid contaminated waterways after a fire at a chemical factory sent toxic smoke billowing over the city.

Firefighters battled the blaze throughout the day and night after a large explosion at the Derrimut factory on Wednesday morning. It came after another fire at the same site resulted in the death of one person last October.

Sign up for Guardian Australia's free morning and afternoon email newsletters for your daily news roundup