Asbestos in Bulk Dust - Benchmarks, Standards and Guidelines Established to Protect Public Health

The following is a description of some the benchmarks, standards and guidelines EPA used to evaluate environmental conditions in the aftermath of the World Trade Center disaster.

If a substance contains 1% or more asbestos, it is considered to be an "asbestos-containing material." There are federal regulations in place to ensure the proper handling and disposal of asbestos-containing material. If a substance contains less than 1% asbestos, these regulations do not apply.

EPA used the 1% definition in evaluating dust samples from in and around ground zero. The vast majority of the samples taken have levels of asbestos below 1%. In fact, in an urban environment like New York City, we can expect the presence of a low level of asbestos under normal circumstances (these low everyday levels are called "background levels").

The majority of areas in which EPA has found levels of asbestos above the 1% definition have been in the vicinity of the work zone at the World Trade Center site.

In examining the data provided by EPA, the public should be careful to distinguish between data that measures asbestos concentrations in the air and from dust samples taken from the ground or other surfaces. Ambient air samples are more accurate indicators of the potential exposure of the public to contaminants. Also, levels of asbestos in the dust and debris vary from location to location. EPA and other agencies found some dust with levels above 1%, but ambient air sampling has not generally revealed concentrations of asbestos at levels that pose significant threats to public health.

View Monitoring Data for Asbestos in Bulk Dust