Testimony to EPA Expert Panel on WTC contamination

September 13, 2004

Marjorie J. Clarke, Ph.D.





The signature – a diversion

The EPA WTC advisory panel has had a fixation on developing a signature for WTC dust from the beginning.  Almost every panel meeting has had presentations in one way or another to settle on one or two pollutants, that if present in particular quantity, signifies WTC dust.  This is a diversion from the real task at hand.  EPA as the ultimate protector of the environment of the country, and the agency with the most resources to do so, should have and should be moving expeditiously to identify indoor locations in which there are hazardous levels of contaminants, and to clean them up.  It would be a huge mistake that if EPA’s sampling program [1] finds toxic dust, that is, dust containing exceedances of health-based benchmarks for one or more contaminants of potential concern as defined in a prior EPA report (COPC), including mercury, [2] EPA does not clean up if their limited signature pollutants (let’s say just vitreous fibers and PAHs) are not present in sufficient quantities.  There could be large amounts of lead or asbestos, cadmium or dioxin, but if the signature pollutants are below EPA’s trigger, it looks like the location would be certified as clean.  This is unacceptable.  It would also be a great quote for a newspaper:  “EPA won’t clean up toxic dust.”  Why wouldn’t the human health impact of whatever dust is found be grounds for a remediation?  Even basic criteria for cleanup on exceedance by any single COPC including mercury, ignores any synergy or multiplied impact of these complex dusts on health, so I argue that a safety factor needs to be included in any benchmarks used for defining these cleanup criteria.  Not only can a signature be misused to preclude cleanup of toxic dust, the use of a signature can be misunderstood by the public as lacking in COPCs for which a signature was lacking (e.g., lead, mercury, vitreous fibers).  The objective should be to clean up, identify failures in emergency response, write up and publicize ‘Lessons Learned’ so that in the event of future environmental disaster, we don’t make the same mistakes again.  I recommend that EPA focus on measuring the pollutants we can measure, see if COPCs are in hazardous concentrations, and if so, schedule a thorough remediation.


How do we determine if there is a hazardous concentration of a COPC including mercury present in a dust?  Despite the fact that EPA has yet to set standards for contaminants in settled dust, except for one, EPA does have other means of determining when soils are contaminated (e.g. to target Superfund sites), and when incinerator ash is hazardous.  EPA should make use of all its own resources to establish benchmarks for toxicity of the dust, and apply a safety factor since these many hazardous air pollutants (the COPCs plus mercury) undoubtedly work together in synergy along with pH and other factors of the dust to produce much greater health impacts than any one of them would alone.


Sampling Universe

Another serious issue is how to sample – which buildings, which units within buildings, and which locations within units are to be sampled?  On p.4. of the Proposed Monitoring Program to Determine Extent of WTC Impact, September 1, 2004, the criteria for building selection are discussed.  But the list of buildings eligible for sampling, which is already being generated assuming that there will be 8-hour, modified aggressive air sampling, will be a smaller list than if EPA indicates that it’s only planning to gather dust.  By the end of the September 13 meeting, it appeared as if the panel supported only the gathering of dust to determine if a building needs remediation.  It is imperative to stop this identification - exclusion - of buildings until it is clear what type of testing will be done.  It is also imperative that EPA include all buildings in its sampling universe that may have WTC dust.  This would include but not be limited to buildings under the plume as seen in aerial photographs.


There is also a serious problem with relying on a self-selected sample of volunteer buildings.  For one, those buildings that were never cleaned would be undersampled because their landlords had been asked to certify to the NYC DEP that their buildings had been remediated.  Such landlords would not want to be caught in a lie.  Also, in p.6 paragraph 2 of the proposed monitoring program it is stated that dust samples taken from inaccessible areas will be caveated.  Since I think I heard that samples will be taken from accumulations of undisturbed dust, where possible, does that mean that EPA will say that data collected in this study is of little value, and therefore an excuse not to do cleaning?


Second, in this paragraph, results of sampling will only be shared with building owners.  And if there is an exceedance, recommendations for cleaning again is given only to owners, and an offer to clean is only given to owners.  I believe it is unethical to withhold health information from tenants (the residents and workers).  Owners have liabilities as I described, and have little motivation, indeed a conflict of interest, to share results, exceedances or offers of cleaning with tenants, so even if there is a major sampling done, and toxic dust is found, getting the cleanup done can be thwarted by the study design’s fixating on inflated importance of a signature, bias in building sampling due to its volunteer nature, and allowing building owners total control over a decision to remediate.  I hope that these flaws in the sampling and remediation program will be remediated.


What should the objectives of this exercise be?  It is essential that once completed, there should be no toxic dust left in interiors of buildings impacted by the World Trade Center collapses and fires.  Therefore, the sampling protocol should be designed to inform where toxic dust remediation should take place.  


In addition, the results of this effort should be to inform studies and cleanups to be performed Immediately After FUTURE environmental disasters (e.g., building collapses and fires – due to terrorism, or even earthquakes).  If there are no lessons learned from 9/11, it would be shameful and reprehensible.

[1] See p.8, paragraph 2 of Proposed Monitoring Program to Determine Extent of WTC Impact, September 1, 2004.

[2] Even more than a year after the WTC disaster, dusts containing mercury are still present in the area, as indicated by surveys taken by Uday Singh with portable mercury monitors, which I witnessed on 2 occasions.