In 2017, NHDES requested assistance from the U.S. EPA’s Office of Research and Development (EPA ORD) to conduct analyses of samples from various media for the potential existence of unique PFAS compounds not previously identified through conventional analysis. One part of this project was for EPA ORD to analyze stack test emission samples taken during the April and May 2018 stack testing at Saint Gobain. These samples were collected by Saint Gobain’s consultant, Barr Engineering, under the watch of NHDES staff. On June 20, 2019, EPA ORD issued a report to NHDES with the non-targeted analysis results of a subset of these samples. Across the three towers sampled, EPA ORD detected 190 PFAS compounds and tentatively identified 89 of them, although without the existence of known standards for each non-targeted compound, EPA ORD could not derive a concentration of these compounds in the samples.
NHDES has evaluated the information from EPA and compared it to the data contained in the Saint Gobain stack test report (Barr Report). Using standard analytical methods, NHDES has tentatively quantified the 89 PFAS compounds. NHDES estimates that the facility-wide annual PFAS emission rate for the 89 compounds is 864 lbs/yr but that the facility has the potential to emit up to 2,326 lbs/yr if all the devices operated 24 hours per day and 365 days per year. To put these emission rates into comparison, the highest estimated level of PFOA emissions alone occurred in 2005 and were 897 lb/yr. Current PFOA emissions are estimated at 0.004 lb/yr. These facility-wide annual PFAS emission levels are likely underestimates for the following reasons:
1. Only 89 of the 190 tentatively identified PFAS compounds are included in these calculations;
2. The results reported are only for three out of seven fractions of each stack test sample;
3. The extraction method used by EPA ORD to remove the PFAS compounds from the stack test samples likely does not get 100% extraction;
4. The methodology does not capture the contribution of non-polar PFAS compounds or volatile polar PFAS; and
5. Additional PFAS compounds were identified but not quantified in the SUMMA canister samples reported in EPA ORD Report #4.
NHDES is using this data as part of the air permit application review to further evaluate the necessary control equipment required to be installed at Saint Gobain.
This report is #6 in a series of reports that will be issued to NHDES by EPA ORD. Additional reports will be provided by EPA ORD as they finish analyses of various media. The June 20, 2019 EPA ORD report can be found at: http://www4.des.state.nh.us/OneStopPub/Air/330110016506202019TypeCR.pdf