Hazards after cyclones and floods

• Broken asbestos sheets and material containing asbestos presents a hazard but exposure to asbestos fibres will be extremely low. Although asbestos material will be damaged, fibres will still be bonded in the cement matrix and are unlikely to become airborne. Nevertheless owners must take precautions to protect themselves and not to break-up and spread asbestos material when returning to their property. Never use power tools on asbestos material.
• If in doubt, treat the material as asbestos.
• Professional asbestos removalist will need to be engaged to assess and remediate to ensure asbestos containing material has been removed even for those properties where the owners may have acted on their own.

You may have damaged asbestos on your property. This will mostly be broken pieces of asbestos sheeting (fences, walls, eaves).

The asbestos in these broken sheets will still be ‘bonded’. That is, the fibres will be held together in the cement matrix so they wont be easily released. Therefore, they present a very low risk for exposure unless you start to break them further.

In general, emergency management authorities will organise specialised asbestos removalists for asbestos clean-up (for large scale damage), so you don’t have to touch it.

However, if you want to clean-up and remove the bonded asbestos sheets and fragments on your property you can do this if you follow the precautions below. If the asbestos can be easily broken when you touch you need to leave it alone. This means it is becoming friable and will require specialist removalists.

Reasonable measures for cleaning bonded asbestos sheets and fragments:

1. Make sure you are wearing adequate personal protective clothing. This includes;
   1. P2 or N95 mask
   2. Disposable coveralls – if available or old clothes that can be disposed later
   3. Gloves
   4. Disposable shoe covers – if available or hard cover shoes that can be cleaned
2. Do not break or crush the asbestos when you are moving it
3. If the material is drying out, keep it wet by lightly hosing with water before moving it
4. Carefully place the asbestos material in 200um plastic bags (heavy duty) or wrap using rolls of 200um plastic
5. If you are placing the asbestos in plastic bags they should NOT be more than half full. Tightly twist the bag opening and fold over to form a goose neck and secure with heavy duty duct. Finally place that bag inside another one (double bag), seal and label ‘DANGER ASBESTOS WASTE’
6. If you are using rolls of black plastic make sure you only wrap the equivalent of a single fence sheet for each wrapping. Double wrap, seal with duct tape and label ‘DANGER ASBESTOS WASTE’
7. Dispose of wrapped asbestos according to the requirements of your local government or emergency advice provided by response agencies.

Cleaning up storm and wind damage asbestos video

It is essential to protect yourself and others when removing storm debris, particularly when asbestos is concerned. The following procedure will help you to safely clean-up after a storm. This video is curtesy of the Queensland Government.

• Electricity networks may be damaged and may not be energised, leaving you without power
  • The top priority will be to make hazards safe, then restoration work will commence as quickly as possible. You may also need to have repairs done to the power lines and poles on your property
  • Be safe – if you see a downed powerline or damaged electrical assets stay at least 8 metres clear and call 13 13 51 to report the hazard to Western Power.
• Mains water may not be functioning due to damaged pipes and/or lack of power to pump water
• Mains gas supplies may be damaged or turned off
• Mobile phone towers may be damaged or not supplied with power to operate (these towers only have limited back up battery power).
• You may not have access to internet services
• Local Government Services may be affected.

Stagnant water left behind by floods and rain provides an excellent breeding ground for mosquitoes increasing the risk of mosquito-borne diseases such as Ross River virus (RRV) and Barmah Forest virus (BFV). In the north of Western Australia there is also the potential for the rare, but potentially fatal, Murray Valley encephalitis (MVE).

Mosquito breeding may occur over vast areas after flooding. You can make a difference by preventing mosquitoes breeding around your home.

Learn more about:

• preventing mosquito breeding at home
• preventing mosquito bites.

Drinking water

Water pipes and storage may be damaged. Before using mains water:

• check with your local council that supplies are safe
• run the taps for a few minutes to remove any contaminated water inside the tap
• thoroughly clean taps and their parts with hot water and detergent
• if you are unsure of the quality of your tap water, use bottled water or boil water before use. However, boiling water will not remove chemical contamination.

Sometimes following a disaster, a boil water alert is issued for areas connected to mains scheme water because the mains water may be unsafe to drink or cook with.

If a boil water alert has been issued, it is essential you follow this warning to prevent illness.

To prepare water for drinking and food preparation, you should heat the water to a rolling boil for at least 1 minute using a stove or kettle and then allow it to cool. This will help to kill any bacteria.

Be sure to keep children clear from any boiling water until the water has cooled down to room temperature.

Once it has cooled it should be placed in the fridge in a clean container with a lid.

Under no circumstances should you drink or cook with water that has not been boiled until the alert is lifted.

Alternatively you can use bottled water.

Cooled boiled or bottled water should be used for:

• drinking
• cooking
• washing raw foods (such as seafood or salads)
• making ice
• cleaning teeth
• your pet’s drinking water.

If a boil water alert has been issued:

• dishes should be washed in hot soapy water or in a dishwasher
• children should take bottled or cooled boiled water to school.

Your local radio station or local government authority (external site) will provide updates. Check their websites for information.

When the boil water alert is lifted, you will need to follow the water supplier’s instructions for flushing the household water pipes.

Find out more about emergency treatment of water supplies.

Rainwater tank contamination

Water in rainwater tanks can be contaminated during a flood by dirty flood waters.

If there is any risk of contamination you should not use the water from the rainwater tank for drinking water purposes until it can be confirmed to be safe.

Tanks may also become breeding areas for mosquitoes.

Action should be taken, as soon as is safe to do so, to ensure mosquitoes are prevented from breeding in these tanks.

In instances where the water is too dirty and cannot be saved, the tank should be drained.

Where the water in the tank can be saved, it needs be properly disinfected.

Using contaminated rainwater

If the water tank has been contaminated in any way, the water can still be used to:

• flush toilets
• water the garden
• wash clothes (providing it will not stain clothes)
• wash cars
• fight fires.

Using any rainwater contaminated with ash or other debris to fill swimming pools or in evaporative air conditioners may clog filters and pumps. Contact the air conditioner, filter or pump manufacturer for advice.

Refilling a rainwater tank

The tank may need to be drained and refilled with water from a commercial water carting company. Make sure that the commercial carting company:

• uses the tanker exclusively for drinking water
• gets the water from a scheme drinking water supply
• has treated the water with at least 1 milligram per litre of chlorine while in transit
• follows the Department’s water carting guidelines (external site).

Bore water

Water drawn from deep bores or wells should be safe to use following a cyclone.

Following flooding, the condition of a garden bore system or water storage tank may be compromised by floodwater entering the system.

Bore water should not be used for drinking or food preparation following flooding. However, some people use bore water for irrigation or laundry purpose.

If this is the case, you will need to disinfect the water from the bore pump to the storage tank. The following disinfection procedure is recommended.

If the tank is clean

If the storage tank is clean, add 1.5 grams of dry pool chlorine per 1000 litres of water to ensure it is safe to use.

If the tank has been contaminated

If the tank has been contaminated you should add 150 grams per 1000 litres for turbid (cloudy) water or 75 grams per 1000 litres for clear water.

The mixture should be left to stand in the tanks for 4 hours.

The tank should then be drained. Do not drink this water.

You can now refill the tank adding 1.5 grams of dry pool chlorine per 1000 litres.

Further information

• Water tanks on your property
• Emergency treatment of drinking water supplies.

How will I know if my septic tank system has been affected?

Cyclones, flood waters or heavy rain may affect or damage your septic tank system, also known as an onsite wastewater system.

This includes 

• septic tanks (primary treatment systems), 
• secondary treatment systems (STS), aerated wastewater treatment systems (AWTS), and their land application systems, for example plastic leach drains, sprinklers and below ground drippers and connection pipes.

Septic tank systems typically comprise a concrete, plastic or fibreglass tank.

Most septic tanks should not be structurally damaged by flooding as they are below ground.

However, flood water may enter your septic tank system through the toilet, other fixtures or the overflow relief gully grate.

Flooding of the septic system may wash out solids from the tank causing blockages or system damage.

Safety issues that need to be checked:

• open covers/pits
• ruptured/leaking systems (including pipes)
• damaged/exposed pipes that may need capping/sealing off.
• failed systems are not easy to identify. However, some simple indicators may include:
• a pungent odour around the tank and land application area
• blocked fixtures, with wastewater overflowing from the relief point
• high sludge levels within the primary tank
• sewage flowing up through the toilet and sinks.

Some onsite wastewater treatment systems may rely on mechanical and electrical equipment, such as pumps, aerators and filters.

This equipment may be damaged by flood or loss of power.

To prevent injury or further damage to your system contact your wastewater service agent.

What can happen to the septic tank during a flood?

Flooding of the chambers in the septic tank or primary/secondary treatment tanks can lift the floating crust. This naturally forms on top of the wastewater and includes:

If the tank becomes flooded, the crust can lift and then block either the inlet or outlet of the septic tank pipes.

This may cause solids to transfer from the septic tank to the leach drain or disposal system.

In addition, septic tanks, leach drains, pump pits and irrigation pipework can fill with silt and debris.

This will either reduce the capacity or the effectiveness of the treatment system.

What should I do if my septic tank has been under flood water?

Do not use any toilets, laundry, kitchen, bathroom or clean-up equipment connected to the onsite wastewater disposal system until:

Contact your local authority environmental health officer for more information.

What should I do if my on-site wastewater system has been damaged by bushfire?

Only trained specialists are suitably equipped to clean or repair onsite waste disposal systems.

This is because tanks may contain dangerous gases and other harmful materials.

Contact your local authority environmental health officer for a list of wastewater disposal system contractors who work in your area.

Onsite wastewater disposal systems should be pumped out by a licensed septic tank operator as soon as possible after the flood.

However, it is important to ensure that the water level in the ground surrounding the tanks is as low as possible before you start.

It is possible for empty tanks to float out of the ground causing damage to underground pipework.

Aerated wastewater treatment system

Aerated wastewater treatment systems (AWTS) should not be used if it has been inundated with floodwater.

Isolate the electrical connection and call the service technician immediately.

A swimming pool may contain debris following a cyclone, floods or heavy rain. This may affect the chemical balance of the water.

Swimming pools should either be emptied or kept chlorinated to prevent the water quality from deteriorating.

Contaminated swimming pools can be:

• a source of odours and bacteria
• a breeding place for mosquitoes
• a health risk to people who use them.

Read more about maintaining water quality for swimming pools and spas.

When disasters cause the power to go out, it generally means the food in your fridge will start to go off.

Unless cold storage (below 4 °C) is available within 2 hours of a power cut, all potentially hazardous foods like cheese that are typically stored in the fridge need to be placed in alternative cold storage, eaten immediately or disposed of.

If in doubt, throw it out.

When you dispose of food, wrap it in newspaper and place in the rubbish bin. A small volume of food may be safely buried.

Where larger quantities have to be disposed of such as for restaurants or cafes, contact the Environmental Health Services at your local government (external site). Without correct disposal, fly breeding may result and increase the risk of the spread of infectious diseases.

Read more about guidelines on food safety and storage, particularly during a power cut.

You should wash dishes that have been exposed to flood water in hot soapy water or in a dishwasher. Make sure the dishwasher is safe to use and has been thoroughly cleaned if it has been contaminated by dirty floodwater.

Vegetable gardens

Floodwater may have contaminated your vegetable or herb garden with bacteria, chemicals or other dangerous substances. Some vegetables may still be all right to eat.

The Department of Health recommends disinfecting in hot water, peeling and cooking the produce to prevent food borne illness.

Floods may bury, move or damage dangerous goods including:

• gas cylinders
• containers of corrosives
• oils
• pesticides
• pool chemicals
• industrial chemicals.

Extreme care must be taken when handling any spills or containers of suspected poisons, chemicals or pesticides, especially if containers are damaged.

Spills or containers of these goods should be isolated until safe management has been arranged.

Damage to containers resulting in a leak or spill

Contact the local fire services branch and any other relevant authority for expert assistance

• Cordon off the area
• Do not wash spillage down drains
• If safe to do so, prevent spread of spilled material by using sand, earth or other commercial spill-containing products
• Minimise the potential for presence of an ignition point or flame in case the chemical is flammable.

General tips for dealing with poisons, chemicals and pesticides

When handling dangerous goods wear personal protective equipment such as chemical resistant gloves, protective eye-wear, enclosed footwear, long-sleeved shirts and trousers.

Ensure that if you are handling drums, you work up-wind and if there is a chemical odour present, wear a respirator with the correct chemically rated filter.

Generators and other fuel-powered equipment should stay outdoors or be placed in a well-ventilated area to prevent the build-up of contaminant exhaust gases such as carbon monoxide.

Use an air monitoring device, such as a gas detector, to monitor the air in enclosed spaces where plant and equipment exhaust is generated.

Try to identify chemicals and their hazards using labels and markings. 

If the label has been removed, seek expert advice and chemical identification from a waste management consultant.

Separate chemicals from general waste, while identifying whether the container is damaged or not and if there is the risk of any chemical reactions. For example, oils and dry pool chlorine may cause a fire if brought together.

Take precautions to protect the area from further damage during the clean-up. This includes preventing mobile plant (earth-moving equipment) coming into contact with containers, particularly gas cylinders; prior to operation check all chemical processing and handling equipment affected by the flood, and ensure a qualified electrician checks electrical installations.

Contact your supplier regarding the safe return to operation for gas supply systems.

Like residents, snakes, rodents and other wildlife can become displaced during a flood or cyclone.

As a result, they may seek shelter and food inside houses, storage sheds and other buildings.

Snakes

After a flood damaged structures and debris are more accessible to snakes.;

When outdoors

Ensure you wear sturdy work boots, gloves, and long trousers to protect your legs and watch where you place your hands and feet when removing or cleaning up debris.
You should remove debris from around your home as soon as practically possible as it can attract rodents, lizards and insects on which snakes feed.

If you see a snake, step back from it slowly and allow it to proceed on its way – do not touch it.

Be aware of snakes that may be swimming in the water trying to get to higher ground, they may also swim towards a boat and attempt to gain entry. They should be warded off with an oar or other long stake.

When indoors

If you find a snake in your house do not panic. Seek advice from the Department of Environment and Conservation on how to get in contact with the nearest licensed snake catcher.

If you are bitten by a snake you should seek medical treatment immediately.

Spiders

If bitten by a red back spider:

• wash the affected area well and soothe the pain with ice packs or clean iced water
• do not apply pressure – this is not recommended for red back spider bites and often worsens the pain
• seek immediate medical help
• for other spider bites
• wash the area with soap and water
• apply a cold pack if the bite is painful.

For most spider bites, no other first aid is necessary. Contact your doctor if symptoms develop or persist

If possible and safe to do so, the spider should be caught for positive identification.

Read more on first aid for bites and stings.

Rodents

To discourage rodents and the spread of disease:

• remove food sources and items that can provide shelter for rodents
• wash dishes and cooking utensils immediately after use
• dispose of garbage and debris as soon as practically possible
• lay rodent baits or traps.

Flies

To discourage flies and the spread of disease:

• do not let food and garbage build up as this becomes a breeding ground for flies
• clean up food wastes as soon as possible.

Following a cyclone or flooding, many animals, particularly farm animals may not survive.

It is important to promptly dispose of animal carcasses to prevent fly breeding, reduce odours, and protect surviving animals from disease.

Landholders should search their property for dead animals as soon as possible after a disaster, provided it is safe to do so. In some cases, carcasses may have commercial value, so consider sending them to a rendering plant if possible.

If rendering is impractical, dispose of the dead animals on the premises.

How to dispose of dead animals

• Cover a carcass with crude oil or kerosene to keep away dogs, scavenging birds and vermin
• Well-fed pigs are the only animal carcasses that will burn satisfactorily. Old railway sleepers can be used as fuel. Burning of other carcasses is not recommended
• Bury other carcasses. Use earth moving equipment if it is available
• Choose a site where subsurface drainage will not reach water supplies
• Bury the carcass at least 90cm to 120cm deep, so predatory animals won't be able to reach them
• If quicklime (Builder’s Lime) is available, cover the carcasses with it before backfilling. Quicklime speeds up the decomposition process.

Contact your local government (external site) animal control officer for further guidelines.

Floods and excessive rain may increase mould and dampness problems in homes that will need to be managed to prevent health problems.

Indoor mould and dampness can also cause unpleasant odours and damage to building materials, contents and structures, which can lead to expensive maintenance or management costs.

Read mould and dampness on reducing mould risks in your home. The Guidelines for Managing Mould and Dampness Related Public Health Risks in Buildings provides detailed information on mould identification and removal.

Recreational waters

After a flood, recreational waters – including lakes, rivers, estuaries and beaches – are likely to be contaminated with sewage and chemicals.

There may also be unpredictable currents, fast flowing water and submerged hazards that are very dangerous.

Never swim in or attempt to drive through floodwaters.

Read more on tips for healthy swimming.

Shellfish

Shellfish includes oysters, mussels, clams, pipis, scallops, cockles, and razorclams.

After a flood, it is almost certain that harmful microorganisms and toxins will be present in waterways (including rivers, lakes, estuaries and the ocean) due to run-off from the land. Do not eat shellfish from flood affected waters as they can make you sick.

Fishing

Fish caught during flood periods should be rinsed prior to scaling and filleting.

Fish should be cooked thoroughly. You should avoid cross contamination between raw and cooked fish.

• Asbestos hazards following a cyclone or flooding (PDF 461KB)
• Chemicals poisons or pesticide hazards following cyclone or flooding (PDF 456KB)
• Clean up following a cyclone or flooding (PDF 477KB)
• Damaged onsite wastewater systems following a cyclone or flooding (PDF 454KB).