Taking care with silt from flooding - HE2967

Floodwaters and the silt they leave behind can be contaminated. They may contain sewage, farm run-off, industrial chemicals, and harmful bugs.

Silt can also include faecal matter (poos) and bacteria that can cause illness such as diarrhoea, skin infections, and leptospirosis.

As flood silt dries, it can turn into fine dust that becomes airborne. Breathing in this dust can irritate or damage your lungs and airways, worsen asthma and other breathing conditions, and irritate your eyes. For these reasons, all flood silt should be treated as contaminated while it remains on your property.

Reduce your exposure at times when there is a lot of dust:

• Try to avoid breathing in dust from silt.
• Stay indoors, close windows, and if you have air conditioning, make sure it is recirculating indoor air and not bringing air in from outside.
• Don’t exercise outdoors.
• Make sure the places you sleep, eat, and relax are dust free.
• Wear the right gear when you are cleaning up or moving silt (i.e. masks, rubber gloves, boots, and eye protection). Cover wounds with waterproof dressings.
• More information is in the Te Whatu Ora Cleaning up a flooded home factsheet

If you can’t avoid dust:

• Wear appropriate personal protective equipment (PPE). This includes wearing a P2/ N95 respiratory mask, gloves, eye protection, protective clothing and sturdy footwear when cleaning up silt or contaminated soil. A cloth mask, a piece of fabric such as bandana, scarf or strips of old sheets can also help prevent dust from getting into your airways.
• Children should only wear masks if they are older than 2. If they’re younger, do your best to keep them away from dust.
• Make sure masks fit correctly. Straps should go above and below the ears.
• Replace masks when needed so they keep working properly.
• Wash your hands thoroughly with soap and clean water after any clean up activities and before eating. Clean and cover any cuts or broken skin.
• If you’re driving through floodwater or silt, slowing down can also help reduce contaminated dust in the air and protect others around you.

If you can’t get rid of silt straight away:

• Try to keep the silt wet if it is creating dust.
• Wear appropriate PPE when cleaning up silt.
• Do not use high-pressure hoses or water blasters. Use only low-pressure water hoses, sweeping damp silt or shovelling it. If high-pressure cleaning cannot be avoided, take extra care with PPE.
• Move silt away to the edge of your section, away from drains. Cover the silt to prevent it drying and blowing around.
• Use barriers to protect the silt from the wind.
• Do not put into your compost.

For more information

• More information on cleaning up after a flood and removing silt is on the NEMA website: Recovery: What to do after a flood » National Emergency Management Agency
• If you are worried about what dust is doing to your health, call Healthline 0800 611 116