The New Jersey Department of Environmental Protection (NJDEP) is currently accepting comment on proposed revisions to the Division of Air Quality Health Risk Screening Worksheet for Long-Term Carcinogenic and Noncarcinogenic Effects and Short-Term Effects. When use of the spreadsheet is applicable, it can be used by facilities as a risk screening assessment to accompany a permit application containing air toxics emitted above the applicable reporting thresholds.

The proposed revisions are being made to align the worksheet with methodologies and assumptions (largely air dispersion modeling related) outlined in Appendix C of Technical Manual 1003 updated in December 2018. It is important to note that the Department's public notice and fact sheet is silent on the significant increase in conservatism that is built into this proposed version of the Worksheet (and the underlying dispersion modeling). To demonstrate this point, a 15 foot stack that is located 100' from the property line was evaluated with the existing worksheet (2018) and the proposed Worksheet (2019). The short-term and long-term predicted impacts are as follows:

Time PeriodUnits2018 WorksheetProposed 2019 Worksheet
1-hour(µg/m3)/(lb/hr)285.503,026.45
Annual(µg/m3)/(ton/yr)12.6931.60

As shown above, use of this proposed Worksheet will likely result in a significantly higher number of sources unable to demonstrate negligible health risk.  These sources will then be required to evaluate risk through refined risk dispersion modeling.  It is important to note that it is not uncommon for sources that generate non-negligible risk using the current worksheet to be able to demonstrate negligible risk through modeling.  Therefore, the increased conservatism in the proposed Worksheet would result in additional burden (and cost) for even more facilities that ultimately demonstrate negligible risk.  Because the underlying modeling for the proposed/revised worksheet is the same as that used for development of the new HAP reporting thresholds in 2018, Trinity is anticipating that dispersion modeling may be required for an overwhelming majority of future permit application with reportable HAPs.

Proposed changes to the existing Worksheet, highlighted in the NJDEP fact sheet and public notice, are listed below.

  • Increase the minimum stack height requirement for sources to use the Worksheet from 10 feet to 15 feet.
  • Add Sulfuryl Fluoride (SF), Carbonyl Sulfide, and 1-bromopropane (n-propyl bromide) to the Worksheet.
  • Addition of nickel refinery dust and nickel subsulfide and their corresponding URFs to the Worksheet. Update the nickel and nickel containing compounds unit risk factor to include these two compounds to ensure consistency with the corresponding reporting thresholds in N.J.A.C. 7:27-17.9(b) Table 2.
  • Update toxicity values (reference concentrations and/or unit risk factors) for the following air toxics currently listed on the Worksheet: benzo(a)pyrene, trimethylbenzene  [(1,2,3), (1,2,4), (1,3,5)], ethylene oxide, chlordane, glutaraldehyde, hydrogen sulfide, toluene, toluene diisocyanate (2,4- and 2,6-), methylene diphenyl diisocyanate (4,4-), tetrachloroethylene (perchloroethylene), ethylene glycol mono-n-butyl ether, and phosphine.

These additions and revisions are based on the latest toxicity data issued by USEPA Integrated Risk Information System, California Environmental Protection Agency, and other recognized scientific entities that identify and characterize the health hazards of chemicals found in the environment.

Please reach out to Trinity's New Jersey office if you would like to learn more about this proposed update to the risk screening worksheet, if you have any questions, or if you want to proactively address the likely results of these potential rule changes. The NJDEP is accepting comments on the proposed changes through June 10, 2019.