Summary

We continue to investigate the environmental impacts to nearby waterways after a chemical fire at Swann Drive, Derrimut.

Fire Rescue Victoria (FRV)  still  controls  the site and is monitoring conditions.  When it is  safe  it will be  handed back to the business and its insurer to manage ongoing demolition and clean up.

What are we doing

Our testing has confirmed water quality in Cherry Creek, Andersons Swamp and the Bay was not affected by the fire.

Kayes Drain and Laverton Creek were most affected on the days immediately after the fire. EPA testing on 11 July detected chemicals including acetone, ethanol and toluene. Careful firewater management, sandbagging and pumping out of contaminated water minimised impacts. Conditions were better than expected. 

Tests taken on  18 July showed all contaminants below any levels of concern. No chemicals at all detected in Laverton Creek near the outlet to the Bay.

Air quality update: no ongoing smoke risk  

Our testing confirmed  ground level air quality was not affected by the smoke. Air monitoring units across Melbourne showed good air quality on 10 and 11 July.

Smoke plume modelling and visual observations showed  the smoke plume rose high in the air above the fire and inversion layer and was diluted.

Vapour monitoring along areas neighbouring impacted waterways and did not detect anything.

Water quality update: returning to normal 

Our testing shows the water quality in Laverton Creek is returning to normal.

Signage warning people to avoid contact with water in the creek has been removed.

Heavy rain in the days and weeks after the fire has also helped dilute the contaminants.

Melbourne Water continues to  manage contaminated firewater run-off offsite for treatment. Sandbags and booms are also in place to control further escapes of wastewater.

We have monitored water quality at multiple locations. This  included Mt Derrimut Golf Course, Fitzgerald and Pipe Roads, Cherry Lake, and Laverton Creek, including Leakes Rd, Victoria, Queen and Merton Streets, and the outlet to the Bay.

The highest impacts were recorded on 11 July at Kayes Drain (which flows into Laverton Creek), and included solvents, detergents and hydrocarbons. While these are now well below any levels of concern, on 11 July, readings from Kayes Drain included: 

• Ethanol (alcohol) - 35,800 micrograms per litre, above the official guideline of 2,400 micrograms per litre
• Toluene - 351 micrograms per litre, above the guideline of 230 micrograms per litre
• Teric N9 (industrial detergent) - 640 micrograms per litre, well below the guideline of 6,400 micrograms per litre 
• Acetone – 6,050 micrograms per litre (no guideline available).

The levels of metals, PFAS and E. coli were all at background levels or not detected.  

We also deployed real-time monitoring water probes to track dissolved oxygen, turbidity. flow, pH and electrical conductivity in the affected creeks. While initial results indicated some lower dissolved oxygen levels in an area of Cherry Creek, this was typical of an urban stream.

No bird or fish deaths have been reported.

Stay informed

We will prepare a public science report soon once all sediment testing results are received. This will explain all the monitoring and science advice we have undertaken throughout this incident.

We continue to work closely with Fire Rescue Victoria and WorkSafe on a longer-term investigations. The timeframe will depend on progress with the clean up and what is found.

We will update our website when further information becomes available.