1,3-Dichloropropene Regulations to Protect Non-occupational Bystanders and Reduce Volatile Organic Compound Emissions
(Effective January 1, 2024)

Back to 1,3-Dichloropropene Regulatory Documents and Activities


On January 1, 2024, regulations to mitigate the potential 72-hour acute risk and 70-year lifetime cancer risk from 1,3-Dichloropropene (1,3-D) to non-occupational bystanders went into effect. The mitigation measures will also further reduce the emissions of 1,3-D as a volatile organic compound. The regulations include the following mitigation measures for acute, non-occupational bystander exposure:

  • Setbacks from occupied structures and general requirements (e.g., application rate and acreage limits);
  • Fumigation method requirements, including the use of totally impermeable film (TIF) tarps; and
  • An annual report that includes summaries of 1,3-D use and air monitoring for the previous calendar year and data analysis if use levels or air concentrations meet specified criteria

These more stringent mitigation measures to address the acute risk to non-occupational bystanders will also mitigate cancer risk to non-occupational bystanders.

Regulation

Documents relied upon

  1. Brajkovich, Laurie. 2022. "APCAC Meeting Update and 1,3-D Proposed Regs," Department of Pesticide Regulation email, August 16, 2022.
  2. Brown, Colin. 2019. "HYDRUS-simulated flux estimates of 1,3-Dichloropropene maximum period-averaged flux and emission ratio for approved application methods," Department of Pesticide Regulation Report, October 17, 2019.
  3. Brown, Colin. 2022. "Updates to HYDRUS-simulated flux estimates of 1,3-Dichloropropene maximum period-averaged flux and emission ratios," Department of Pesticide Regulation Report, September 22, 2022., PDF
  4. Brown, Colin. 2023. "Modeling broadcast-strip TIF applications with 40% tarp coverage," Department of Pesticide Regulation Report, April 3, 2023.
  5. DPR. 2016a. "Response to comments by OEHHA on DPR-HHAB’s draft 1,3-Dichloropropene risk assessment document (dated August 31, 2015)." August 6, 2016. Department of Pesticide Regulation.
  6. DPR. 2016b. "Response to comments by US EPA on DPR-HHAB’s draft 1,3-Dichloropropene Risk Characterization Document dated August 31, 2015." September 8, 2016. Department of Pesticide Regulation.
  7. DPR. 2016c. "Responses to comments by Dr. Urmila P. Kodavanti on DPR-HHAB’s draft 1,3- Dichloropropene Risk Characterization Document dated Aug. 31, 2015." September 8, 2016. Department of Pesticide Regulation.
  8. DPR. 2016d. "Responses to comments by Dr. Richard A. Fenske on DPR-HHAB’s draft 1,3- Dichloropropene Risk Characterization Document dated November 19, 2015." September 8, 2016. Department of Pesticide Regulation.
  9. DPR. 2016e. "Responses to comments by Dr. Weisueh A. Chiu on DPR-HHAB’s draft 1,3- Dichloropropene Risk Characterization Document dated August 31, 2015." September 14, 2016. Department of Pesticide Regulation.
  10. DPR. 2016f. "Response to comments by Dow AgroSciences on DPR-HHAB’s draft 1,3- Dichloropropene Risk Characterization Document dated Aug. 31, 2015." November 8, 2016. Department of Pesticide Regulation.
  11. DPR. 2015b. "1,3-Dichloropropene Risk Characterization Document: Inhalation Exposure to Workers, Occupational and Residential Bystanders and the General Public." December 31, 2015. Department of Pesticide Regulation.
  12. DPR. 2019. "Responses to the External Peer Review of the Methodology to Develop a Township Cap for 1,3-Dichloropropene." May 2019. Department of Pesticide Regulation.
  13. DPR. 2021. "Comments on the September 28, 2021 Draft Risk Management Directive for 1,3-Dichloropropene and Responses." October 2021. Department of Pesticide Regulation.
  14. DPR. 2022a. "Review by the Toxic Air Contaminant Workgroup of Documents Related to the Draft 1,3-Dichloropropene Regulations," Department of Pesticide Regulation document, November 7, 2022., PDF
  15. DPR. 2022b. "Agricultural Pesticide Control Advisory Committee Agenda, December 14, 2022." Department of Pesticide Regulation.
  16. DPR. 2022c. "Overview of Draft 1,3-D Regulations," Department of Pesticide Regulation email, August 15, 2022.
  17. DPR. 2022d. "Pesticide Registration and Evaluation Committee Agenda, November 18, 2022." Department of Pesticide Regulation.
  18. Edwards, David. 2022. "OEHHA’s Response to DPR’s Request for Agreement Regarding DPR’s Development of a Regulation to Mitigate Risks to Non-Occupational Bystanders from 1,3-D Use," Office of Environmental Hazard Assessment memorandum, September 20, 2022.
  19. Goodhue, R., K. Mace, S. Blecker, Y. Zheng, J. Rudder, A. Spalding, T. Tolhurst, H. Wei, B. Gress, and J. Steggall. 2022a. Economic and pest management evaluation of proposed 1,3-Dichloropropene. University of California, Davis and California Department of Food and Agriculture Report, June 21, 2022.
  20. Goodhue, R., K. Mace, S. Blecker, Y. Zheng, J. Rudder, A. Spalding, T. Tolhurst, H. Wei, B. Gress, and J. Steggall. 2022b. Addendum to the June 2022 economic and pest management evaluation of proposed 1,3-Dichloropropene regulation. University of California, Davis and California Department of Food and Agriculture Report, June 23, 2022.
  21. Goodhue, R., K. Mace, S. Blecker, Y. Zheng, S. Raburn, J. Rudder, A. Spalding, T. Tolhurst, H. Wei, B. Gress, and J. Steggall. 2023. "Addendum to the June 2022 Economic and Pest Management Evaluation of Proposed 1,3-Dichloropropene Regulation," University of California, Davis and California Department of Food and Agriculture Report, March 13, 2023.
  22. Henderson, Julie. 2021. "Risk Management Directive and Mitigation Guidance for Acute, Non-Occupational Bystander Exposure from 1,3-Dichloropropene (1,3-D)," Department of Pesticide Regulation Memorandum, October 19, 2021.
  23. Kandelous, Maziar. 2019. "A comparison between field-estimated and HYDRUS-simulated emission of 1,3-Dichloropropene from agricultural fields," Department of Pesticide Regulation Report, October 17, 2019.
  24. Kandelous, Maziar. 2022. "Developing mitigation measures for 1,3-Dichloropropene applications: An overview of the Pilot Studies." Department of Pesticide Regulation Report, October 11, 2022., PDF
  25. Luo, Yuzhou and Colin Brown. 2022. "Modeling for application factors of 1,3-Dichloropropene, modeling approach #2," Department of Pesticide Regulation Report, September 12, 2022.
  26. Luo, Yuzhou and R. Uyeda. 2023. "Modeling the high detections of 1,3-Dichloropropene in DPR’s Air Monitoring Network," Department of Pesticide Regulation Report, April 3, 2023.
  27. Luo, Yuzhou. 2019a. "Evaluating AERMOD for simulating ambient concentrations of 1,3-Dichloropropene," Department of Pesticide Regulation Report, October 17, 2019.
  28. Luo, Yuzhou. 2019b. "AERFUM: an integrated air dispersion modeling system for soil fumigants," Department of Pesticide Regulation Report, October 17, 2019.
  29. Luo, Yuzhou. 2022a. "Modeling for mitigation measures to reduce acute exposure from 1,3-Dichloropropene, modeling approach #2," Department of Pesticide Regulation Report, September 12, 2022., PDF
  30. Luo, Yuzhou. 2022b. "Modeling for mitigation measures to reduce acute exposure from 1,3-Dichloropropene, modeling approach #1," Department of Pesticide Regulation Report, September 12, 2022., PDF
  31. Luo, Yuzhou. 2022c. "Modeling for the township cap of 1,3-Dichloropropene applications, modeling approach #2," Department of Pesticide Regulation Report, September 12, 2022., PDF
  32. Luo, Yuzhou. 2023. "Addendum: Modeling for mitigation measures to reduce acute exposure from 1,3-Dichloropropene, Revised setback tables," Department of Pesticide Regulation Report, April 3, 2023.
  33. Luo, Yuzhou. 2023a. "Addendum: Modeling for mitigation measures to reduce acute exposure from 1,3-Dichloropropene, Applications with a minimum soil moisture of 25% of field capacity," Department of Pesticide Regulation Report, April 3, 2023.
  34. Mace, Kevi. 2022. "Number of Farms Using 1,3-Dichloropropene," California Department of Food and Agriculture memorandum, August 4, 2022.
  35. Mace, Kevi. 2023. "Number of Farms Using 1,3-Dichloropropene - updated," California Department of Food and Agriculture memorandum, April 4, 2023.
  36. Marks, Teresa. 2016a. "Comments on the Draft Risk Management Directive for 1,3-Dichloropropene (1,3-D) and Responses." Department of Pesticide Regulation Letter, October 6, 2016.
  37. Marks, Teresa. 2016b. "Risk Management Directive and Mitigation Guidance for Cancer Risk from 1,3-Dichloropropene (1,3-D)," Department of Pesticide Regulation Memorandum, October 6, 2016.
  38. Morrison, Karen. 2022. "Request for OEHHA Agreement Regarding DPR’s Development of a Regulation to Mitigate Risks to Non-Occupational Bystanders from 1,3-D Use," Department of Pesticide Regulation letter, September 16, 2022.
  39. Rubin, Daniel. 2022. "Analysis of the applicability of Food and Agricultural Code sections 12980 and 12981 to proposed 1,3-Dichloropropene regulations addressing acute and cancer risk to non-occupational bystanders," Department of Pesticide Regulation memorandum, October 17, 2022.
  40. Segawa, Randy and Yuzhou Luo. 2022. "Analysis of the Sufficiency of Acute Mitigation Measures to Mitigate Cancer Risk from 1,3-Dichloropropene," Department of Pesticide Regulation Memorandum, November 3, 2022., PDF
  41. Tuli, Atac and Delgado, Yvan. 2022. "Analysis of high barrier tarpaulin cis-1,3-Dichloropropene mass transfer coefficient data measured under high relative humidity conditions," Department of Pesticide Regulation Memorandum, September 20, 2022., PDF
  42. Tuli, Atac, Colin Brown and Yvan Delgado. 2022. "Guideline to determine soil water content (moisture) at field capacity," Department of Pesticide Regulation Report, September 20, 2022., PDF
  43. USDA. 1998. "Estimating Soil Moisture by Feel and Appearance." U.S. Department of Agriculture, Natural Resources Conservation Service, Program Aid Number 1619, April 1998.