Fluoride Action Network

California pesticides division discusses sulfuryl fluoride

Source: California Pesticide Registration and Evaluation Committee (PREC) | July 18th, 2014 | Meeting Minutes
Industry type: Pesticides

Introductions and Committee Business -Ann Prichard, Chair, DPR

a.       About thirty-five (35) people attended the meeting.

b.      No corrections to the previous meeting minutes, held on May 16, 2014 identified.

2.    Sulfuryl Fluoride (Structural) Mitigation Efforts

Kevin Solari, DPR, Linda O’Connell, DPR, and Pam Wofford, DPR

In September 2006, DPR completed a Risk Characterization Document (RCD) for sulfuryl fluoride used in structural and non-food commodity fumigations and identified exposure scenarios of concern: worker, bystander, and residential exposure, based on limited data and using health-protective factors to compensate for data uncertainties. In April 2007, DPR issued a Risk Management Directive (RMD) based on the RCD for sulfuryl fluoride use in structural and non-food commodity fumigations requiring the mitigation of acute and repetitive worker exposures, and acute exposures for residents and bystanders. This RMD stated acute exposures to sulfuryl fluoride should not exceed the 24-hour time-weighted average reference concentrations of 2.57 ppm (10.7 mg/m3) for workers and 0.12 ppm (0.51 mg/m3) for bystanders and residents. DPR defines a bystander as persons living or working in proximity to a fumigated structure. Note, the 0.12 ppm (0.51 mg/m3) for bystanders is due to an additional safety factor and DPR is missing a delayed neurotoxicity study.

In June 2007, sulfuryl fluoride was designated a toxic air contaminant (TAC) in regulation (Section 6860(a)) and a year later, DPR initiated reevaluation of sulfuryl fluoride products intended for structural fumigation due to the RCD. An additional concern was the decrease in the permissible reentry concentration for sulfuryl fluoride from 5 ppm to 1 ppm, as defined on the 2006 labels. The tarpaulin removal and aeration plan (TRAP) was developed to protect workers and removed excess sulfuryl fluoride. Since TRAP was not developed to meet 1 ppm threshold, a concern arose that TRAP might not be adequate to address the new label changes.

DPR requested data to assess if TRAP, or another method, is adequate to reduce risks to workers, bystanders, and residents. During the course of this reevaluation, the California Aeration Plan (CAP) was developed to lower worker exposure and concentration to 1 ppm. First implemented in November 2010, CAP replaced TRAP. The studies submitted to DPR under sulfuryl fluoride reevaluation used this CAP method. Review of these studies indicates use of the new CAP method reduces acute and repetitive worker exposures to sulfuryl fluoride used in structural fumigations. The sulfuryl fluoride reevaluation concluded in March 2013 and subsequently, CAP2 was implemented May 2013 to further improve indoor aeration and to address aeration duct placement and construction.

Meanwhile, the TAC law was recently amended (FAC sections 14022, 14023, and 14024) to require DPR to adopt mitigation measures within two years of a decision to mitigate a pesticide that is determined to be a TAC, effective January 1, 2014. DPR is currently evaluating sulfuryl fluoride data and exposures to bystanders and residents to assess potential mitigation strategies.

In the beginning of the mitigation process, DPR investigates information on how the active ingredient is used. The top three counties for structural use from 2008 to 2012 are Los Angeles, Orange, and San Diego. Seventy-nine percent of structural use of sulfuryl fluoride occurred in Southern California. Of the illness cases reported from 2005 to 2010, twenty-three percent occurred in lower use counties.

DPR intends to use air dispersion modeling with the AMS/EPA Regulatory Model (AERMOD). Since AERMOD is new to DPR, DPR has requested ARB’s assistance with this modeling. The Environmental Monitoring Branch of DPR will develop the AERMOD modeling procedure for the simulation of structural fumigations by viewing past data and to determine the specific modeling set-up during Phase I. Phase II will model the potential exposure of sulfuryl fluoride in residential areas of counties with most use of structure fumigation and to develop mitigation measures to reduce the health risk to bystanders in these areas. DPR plans to model fumigations in Alameda County, Los Angeles County, San Bernardino County, San Diego County, and Santa Clara County.

The Worker Health & Safety (WHS) Branch of DPR is using direct reading instrumentation that reads to 0.3 ppm to characterize the concentration gases. From preliminary work, the gas appears to leak through the seals. WHS’s goal is to characterize the gas to lower the concentration during the fumigation process. WHS recognizes the concern of exposure during the aeration process and is interested in the period for the exposure during aeration. The currently difficulty is the air samples collected in the past are composite air samples, integrated samples collected on charcoal. This method of data is collected over a course of hours so the concentration during the initial exposure cannot be determined. WHS is planning on collecting data and collaborating on a study with industry this summer.

5.      Public Comment and Questions

Charles Salocks inquired how DPR defines the sulfuryl fluoride illness cases and if a medical professional determined the illness cases were due to exposure.

Kevin Solari responded that the pesticide illness surveillance program determines the validity of the case.

James Seiber inquired about which chemicals, if any, are used as an alternative to sulfuryl fluoride.

Kevin Solari stated sulfuryl fluoride has taken methyl bromide’s place and currently, there are no competing pesticides. The non-chemical alternatives include heat treatment, infrared, and orange oil.

David Luscher questioned the high use of sulfuryl fluoride in Southern California.

Dr. Brian Bret stated the pesticide is largely used for dry wood termites and Southern California is more prone to this type of pest.

Dr. Brian Bret questioned how DPR receives the illness cases for sulfuryl fluoride.

Linda O’Connell replied DPR receives the cases from medical professionals.

David Luscher inquired if the concern regarding bystanders is during aeration or the fumigation process.

Pam Wofford stated the concern is during both as ARB has collected some data with a concern for the concentration.

Lynn Baker inquired if neighboring residents are assumed to have windows closed and inside their home during nearby aeration and fumigation and why DPR would look into the information.

Linda O’Connell stated the concentration is assumed to be equivalent whether inside or outside the home and DPR is gathering all possible information.

Rebecca Sisco inquired if 24-hour time-weighted average is the original aeration time and if the time can be lengthened or shortened.

Linda O’Connell stated the 24-hour time-weighted average is an exposure period that DPR toxicologists determined.

Rebecca Sisco further inquired about the length of time it takes to aerate a structure.

Linda O’ Connell stated that it typically takes twelve hours to aerate a structure. However, a formula is used to include the type of pest, the concentration, the amount of pesticide, and the size of the house. There is an active aeration period and it appears it takes a full day for the fumigation to occur and then another day for the active aeration to occur and then the clearance is conducted on the third day.

Rebecca Sisco asked how long it took clearance to occur, as it is her understanding the highest exposure rate occurs then.

Linda O’Connell stated the exposure during the clearance is not an issue with the aeration and clearance procedures in place.

Rebecca Sisco inquired the how long the time period is for worker exposure during the opening process of fumigation.

Dr. Brian Bret stated in the past, workers would take down the tarps as the fumigation concluded and exposure to workers to any residual fumigants would then occur. Currently, the CAP procedure uses active ventilation before the removal of tarps to expel any residual fumigants. With the CAP procedure in place, the worker exposure is little to none and is assumed the exposure is less than 1 ppm.

Dr. James Seiber inquired if there was data showing any ambient exposure due to fumigants. Linda O’Connell stated there have been seven illness cases due to fumigation of neighboring structures.

Lynn Baker commented that there should be an advanced public notification when active aeration is taking place to adjacent bystanders.

Charles Salocks inquired if there were any illness cases reported other than upper respiratory problems and if DPR’s Medical Toxicology Branch follows up on the cases.

Linda O’Connell stated the vast majority of the symptoms could be related to chloropicrin and the Medical Toxicology Branch does not follow up on the cases. The county conducts an investigation of the illness and the county reports the investigation to DPR’s WHS.

Justine Weinberg asked if WHS could look at chloropicrin levels along with the sulfuryl fluoride evaluation. Linda O’Connell stated DPR is looking at chloropicrin levels at least in the reentry of homes.

Anne Katten commented that it might be important to factor in the type of ventilation system the home has in the sulfuryl fluoride evaluation.

Charles Salocks inquired if the outcome of the brodifacoum reevaluation meant there was a shift in the use and if DPR compared brodifacoum levels in the animals analyzed in the wildlife incident and mortality data to the land use data, and sales and use data received by DPR. Ann Hanger stated DPR analyzed all the SGAR chemicals and all the SGARs are restricted materials.

David Luscher inquired whether there are lawn fertilizer products that incorporate pyrethroids and if there is a concern in possible overuse. The Scotts Company is one of the large lawn fertilizer registrants and voluntarily removed all combination products.

Dr. James Seiber asked whether there were any concerns of pyrethroid residues in homegrown foods as well as commercial agriculture. Carlos Gutierrez stated there are food tolerances for commercial agriculture and for the home user, there are application rates listed on the label.

Dr. James Seiber further inquired if there was data relating to home use of pyrethroids.

Carlos Gutierrez stated there is data for food tolerances per the Code of Federal Regulations, Title 40, Section 180. Ann Prichard stated the reevaluation process is required to be focused and the pyrethroid reevaluation focused on toxicity to aquatic organisms. DPR has other branches that look into toxicity and food residue data. C

arlos Gutierrez stated DPR has the food safety program in place to take samples to ensure residues on commodities are not above the residues established.


Committee Members/Alternates in Attendance:

Ann Prichard, Department of Pesticide Registration (DPR)
Charles Salocks, Office of Environmental Health Hazard Assessment (OEHHA)
David Luscher, Department of Food and Agriculture (CDFA)
David Ting, OEHHA
James Seiber, University of California (UC), Department of Toxicology
Jeff Fowles, Department of Public Health (CDPH)
Jodi Pontureri, State Water Resources Control Board (SWRCB)
Lynn Baker, Air Resources Board (ARB)
Patti TenBrook, U.S. Environmental Protection Agency (EPA), Region 9 -via webcast
Rebecca Sisco, University of California (UC), IR-4 Program
Stella McMillin, Department of Fish and Wildlife (DFW)
Valerie Mitchell, Department of Toxic Substances Control (DTSC) -via webcast

Visitors in Attendance:

Aimee Brooks, CA Cotton Ginners and Growers Assoc./Western Agricultural Processers Assoc.
Andi Cameron, DPR -Pesticide Registration
Ann Hanger, DPR -Pesticide Registration
Anne Katten, California Rural Legal Assistance Foundation
Artie Lawyer, Technology Sciences Group
Brian Bret, Dow AgroSciences
Carlos Gutierrez, DPR -Pesticide Registration
Ed Wilson, Ensystex
Eryn Shimizu, DPR -Pesticide Registration
Jeanne Martin, DPR -Enforcement Headquarters
Jennifer Teerlink, DPR -Environmental Monitoring
Jill Townzen, DPR -Pesticide Registration
Joshua Adams, Pest Control Operators of California
Justine Weinberg, CDPH
Ken Kendall, Ensystex
Kevin Solari, DPR -Worker Health & Safety
Linda O’Connell, DPR -Worker Health & Safety
Lisa Zwicky, DPR -Personnel Services
Naeem Ahmad, DPR -Pesticide Registration
Pam Wofford, DPR -Environmental Monitoring
Rima Woods, OEHHA
Rachel Kubiak, Western Plant Health Association
Terry Davis, Univar
Tom Estill, Ensystex