Sulfuryl fluoride is the most important structural fumigant in the United States for the treatment and control of structure-infesting pests. Scientists have shown that fumigation is a reliable and complete method for elimination of infestations of drywood termites and other pests such as wood-destroying beetles and bed bugs, in buildings.

About 100,000 fumigations with sulfuryl fluoride are conducted each year in California. Costs for control and repair of damage from drywood termites in California exceeds $300 million annually and are projected to increase.

There are many procedures that minimize the potential exposure of fumigators and other people to sulfuryl fluoride during structural fumigation. Some of these are illustrated below with photos the PCEP researchers captured during monitored fumigations.

The warning agent, chloropicrin, is introduced into the building per label directions prior to the introduction of the fumigant sulfuryl fluoride. Chloropicrin serves to warn of the presence of the odorless and colorless sulfuryl fluoride and is a deterrent to intruders. Chloropicrin is ventilated from the building with the sulfuryl fluoride during aeration (Photo A).



All exterior entrances and sides of the fumigated building are posted with warning signs during the fumigation process. In addition to stating the name of the fumigant used and warning against entry, the signs contain 24-hour contact information for the fumigation company (Photo B).



All exterior entrances are barricaded or locked with special locking devices. This procedure prevents residents from using their keys to re-enter during the fumigation process (Photo C).





Fumigators must wear respiratory protection (SCBA-Self Contained Breathing Apparatus) if they enter the fumigated space before it is aerated. NOTE: The new California Aeration Plan was developed so fumigators would not need to enter the fumigated space to initiate aeration (Photo D).



Fumigators must follow detailed, validated procedures during the California Aeration Plan (CAP). These procedures specify the type of ventilation equipment used, such as ducting and fans with required capacity to move air, and the duration of ventilation period using fans (Photo E).



After completion of aeration, the fumigator must test the air in each room using the Interscan or SF-ExplorIR to confirm aeration of the fumigant before allowing reoccupancy of the building (Photo F).

Toxic Air Contaminant: As defined by California Health and Safety Code, Section 39655 (a): an air pollutant which may cause or contribute to an increase in mortality or in serious illness, or which may pose a present or potential hazard to human health. Substances which have been identified by the U.S. EPA as hazardous air pollutants (e.g. benzene, asbestos) shall be identified by the Board as toxic air contaminants.

Of course, an air contaminant is toxic only if air concentrations are high enough to cause adverse effects (toxicity) in persons who are exposed.

Research and the chemical properties of sulfuryl fluoride demonstrate that this fumigant will not adversely affect water or soil when used according to the label directions.

Sulfuryl fluoride has very low solubility in water (e.g. compared to sugar, salt or other soluble chemicals). This beneficial feature of the product is why the product label recommends watering the perimeter of the foundation prior to tarped fumigations. Water acts as a barrier to minimize movement of sulfuryl fluoride into the soil between tarps and the building, improving confinement of fumigant during the fumigation.

No, listing of sulfuryl fluoride and chloropicrin as TACs does not affect their label use directions. The regulatory standards for air levels have been reduced based upon scientific review of data from structural fumigation during application and aeration.

The TAC listing process is an additional step required by State law in California to identify materials that may be found in air. It is in addition to the actual risk characterization analysis done by California Department of Pesticide Regulation (DPR) and includes a separate review. Some other common chemicals listed as TACs include chlorine, formaldehyde, methanol, naphthalene, and toluene.

No. Due to the physical properties of sulfuryl fluoride, this fumigant does not accumulate inside a building following label-directed fumigation and aeration procedures. For fumigation the release of sulfuryl fluoride into the indoor air creates the natural force that drives sulfuryl fluoride gas into the depths of wood where drywood termites thrive. The driving force during fumigation is a concentration gradient---sulfuryl fluoride moves from the indoor air through the wood and other materials to the microscopic air spaces where no fumigant gas previously existed. The process is very rapid. During aeration the process is reversed when the fumigant concentration is rapidly reduced in the indoor air. The higher concentrations within wood and other materials is rapidly reduced as sulfuryl fluoride comes out of the air spaces in the wood, the structure, and its contents during the aeration process after the fumigation seals to outside air are opened.

Toxic concentrations of sulfuryl fluoride are maintained indoors during fumigation by tarping to seal fumigant inside the structure. The fumigant penetrates materials readily and it is very important that the process works both ways (fumigant going in and coming out)! When aeration begins and the structure is ventilated, the off-gassing also occurs very rapidly. Following the California Aeration Plan, the residence is tested using sensitive detection equipment to confirm fumigant concentrations are 1 ppm or less, and is ready for reoccupancy.

The driving force continues to be low air levels going to still lower ones down a concentration gradient. If buildings and materials retained sulfuryl fluoride, then fumigators would not need to use elaborate procedures, including tarpaulins, polyethylene sheeting, and tape, to seal structures to keep sulfuryl fluoride inside during the fumigation. Sulfuryl fluoride concentrations continue to decline to non-detectable levels following aeration even without the aid of circulation fans and with closed windows and exterior doors.