Barclay Damon
Barclay Damon

Legal Alert

NYSDOH Cuts Indoor Air Guideline for TCE in Half

The New York State Department of Health (NYSDOH) just released a revision to its indoor air guideline for trichloroethylene (TCE). This revision will affect a large number of remedial sites in New York State because TCE was a common industrial and dry cleaning solvent.

Moreover, as a volatile organic compound, TCE is known to readily volatilize from groundwater and soil particles into sub slab soil vapor, and soil vapor intrusion considerations are now driving a good deal of remedial decision making.

In its new guidance, NYSDOH has reduced the indoor air guideline for TCE from 5 micrograms per cubic meter (ug/m3) to 2 ug/m3. By doing so, NYSDOH has come into line with USEPA’s 2011 recommended reference concentration of 2 ug/m3 TCE.

However, NYSDOH has not provided any information on how this change affects the use of the decision making matrix set forth in its Guidance for Evaluating Soil Vapor Intrusion in the State of New York which guides whether mitigation will be required when TCE is present at varying concentrations in the indoor air and associated sub slab vapor.

NYSDOH has nevertheless included a new concept in its revision that encourages “immediate and effective action” should indoor air concentrations equal or exceed 20 ug/m3 TCE. Further, NYSDOH is recommending action be taken to reduce exposure below background levels which it defines as <1 ug/m3 TCE for both indoor and outdoor air.

While the NYSDOH noted many adverse health effects (kidney cancer, liver cancer reproductive effects, central nervous system effects) linked to TCE exposure, in explaining how it derived its new indoor air guideline, NYSDOH appears to have been focusing on both continuous exposures to TCE air concentrations for months or as long as a lifetime, and sensitive populations (for example children and pregnant women).

The revised indoor air guideline “was set at an air concentration that is lower than air concentrations known to cause, or suspected of causing, effects in humans and animals.” NYSDOH believes that the new guideline is adequately protective of the public health.


If you require further information regarding the information presented in this Legal Alert and its impact on your organization, please contact Tom Walsh at (585) 295-4414 or twalsh@barclaydamon.com or either Co-Chair of the Environmental Practice Area Frank Bifera, at (518) 429-4224 or fbifera@barclaydamon.com or Yvonne Hennessey, at (518) 429-4293 or yhennessey@barclaydamon.com.