The terrorist attack on the World Trade Center in New York on 9/11 may be the greatest asbestos disaster to ever happen. Over 3,000 were killed in the attack; the number killed by the released asbestos from that attack could be 100 times that.

The World Trade Center had all its structural steel fireproofed with asbestos fireproofing.

The expert panel of architects, engineers and metallurgists determining the cause of the collapses came to the following conclusions.

When the planes hit the Towers, their gas tanks exploded and blew all the asbestos fireproofing off the structural steel on the attacked floors. This fire ball also set all the paper and furniture on fire. After 20 minutes, the heat of these fires reduced the strength of the structural steel so that a couple of floors collapsed. These collapsed floors took the rest of the buildings with it.

An old photo of the World Trade Center twin towers in New York, U.S.A.

An old photo of the World Trade Center twin towers in New York, U.S.A.

We have all seen the grey dust engulfing the World Trade Center area after the collapse. A huge percentage of that dust was asbestos fibres. First responders (fireman, policemen, paramedics and volunteer citizens), building evacuees and on lookers got a lifetime dosage of asbestos in a few minutes from this grey cloud. To-day – 20 years later – asbestos related problems are starting to occur in people exposed to this grey cloud of asbestos fibres.

Asbestos, if left in place and in good condition, is not a significant health concern. It is when it is disturbed that it becomes a problem. In New Zealand, asbestos abatement before a renovation of a public building prevents asbestos fibres from becoming airborne.

Other sources of airborne asbestos are weathering of asbestos containing roofing and cladding exposes asbestos fibres. (The infamous “fuzzy” looking cladding). There are also some accidental releases as when someone chips of a piece of ornamental plaster or punctures the protective cladding around pipe insulation. The repair and removal of these asbestos problems can be planned and quickly fixed.

Natural disasters like flooding and earthquakes can result in a large amount of asbestos containing materials being damaged. The damage can be very expensive to fix. Human exposure to asbestos fibres effects won’t be known until many years later. 

The recent earthquake in Christchurch is a good example. The earthquake caused a lot of damage to asbestos containing materials. The asbestos removal costs were high for the following reasons:

  • Safety measures had to be taken to a damaged or collapsed building to ensure there was no further collapse during asbestos removal.

  • Normally a couple of bins would contain all the asbestos containing materials from a building. But after the earthquake many bins were required because non asbestos materials were contaminated by asbestos fibres. This large volume of waste filled existing landfills. New landfills will have to be built sooner than planned.

  • The site expense of asbestos removal from damaged or collapsed buildings was a lot more expensive than that of asbestos removal in an undamaged building. Larger more complicated containment structures must be built to allow asbestos removal; workers must be careful to not further damage the building, and the volume of material to be removed is much larger. All these extra expenses result in large labour costs.

“Toxicity is in the dosage” is the same for asbestos as it is for other toxins. A small amount of arsenic will not be noticed; a larger amount will make you sick and a large dosage will kill you. The same is true for asbestos. The only difference is, as shown by the 9/11 disaster, asbestos problems don’t usually surface for many years.

In Christchurch, as most people’s exposure was of minimal duration and concentration, they are not in much danger of future related asbestos problems. The asbestos removers had personal protective equipment to prevent their exposure to asbestos particles. Based on the 9/11 disaster, the first responders may or may not have future problems based on the amount of protective equipment they were wearing; the concentration of asbestos fibres they were exposed to and the length of time that they were exposed. We’ll know if the first responders had problems in twenty years or so.


New Zealand’s Worksafe requires that all buildings are required to have asbestos management plans.

The national government and councils should look at revising their management plans to make immediate asbestos removal in their buildings a top priority.

Safety for first responders is the primary reason. No one in an emergency is going to let someone die or suffer because he or she may have a problem in 20 years.

If there are minimal asbestos releases, everybody can concentrate on other problems caused by a natural disaster.

Asbestos removal now is cost justifiable. Removal from an existing structure is much cheaper than removal from a damaged structure. Landfills are expensive to build. With no asbestos removal required, damaged buildings can be quickly replaced or repaired.