Department of Pesticide Regulation
Chris Reardon
Acting Director
  Edmund G. Brown, Jr.
October 17, 2011
  ENF 11-25 (AMENDED)
County Agricultural Commissioners

Soil fumigant labels and use requirements have changed during the past year. The label revisions mandated by the U.S. Environmental Protection Agency (U.S. EPA) included limiting certain application methods, requiring fumigant management plans, and making all soil fumigants federal restricted use products. In addition, the Department of Pesticide Regulation (DPR) issued recommended permit conditions for MITC-generating soil fumigants. The March 2011 letter ENF 11-09 gives a summary of the changes.

In late 2011, U.S. EPA plans to require further label revisions which will include additional buffer zones, credits to reduce emissions, posting of buffer zones, etc. For information about U.S. EPA’s future label changes in 2011 for 2012, see their website at:

DPR and U.S. EPA recently conducted joint training sessions on the 2010 U.S. EPA label requirements and the new DPR recommended permit conditions for MITC-generating soil fumigants. The following questions were raised during the training sessions.

This October 2011 letter replaces the August 2011 version by revising or clarifying the answers to questions 1, 11, 17, 28, 35, 40, 43, and 47, and adds number 33B.


1.  When there are differences between labeling, permit conditions, and regulations, which requirement should be followed and enforced?

The most restrictive requirement is enforced, unless there is current DPR guidance specific to soil fumigants. There are two instances where DPR guidance has been applied to the new soil fumigant labeling. They are the use of check boxes on the California fumigant management plan (see question number 33B) and the use of air monitoring devices when applying methyl bromide products that contain 80% or less methyl bromide (see question number 43).

2.  What sources of information can CAC staff use to answer the public’s questions on the risks of soil-applied fumigants?

Conducting Inspections

3.  Will field fumigation inspection forms be changed to reflect these changes?

No, we do not anticipate changing any inspection forms in the near future. Compliance with all requirements associated with the new labeling during a Field Fumigation Use Monitoring inspection should be addressed in Requirement 10, "Labeling - Site/Rate/Buffers/Other" (Food and Agricultural Code (FAC) 12973). Compliance with all requirements associated with the new labeling during a Headquarter and Employee Safety inspection should be documented in the blank line(s) at the bottom of the Requirements section citing FAC section 12973.

4.  Will the Inspection Procedures manual be changed to reflect these changes?

Yes, we will amend the Compendium chapters on Field Fumigation Use Monitoring Inspections, Pest Control Headquarters Inspections and Pest Control Business Headquarters Inspections to reflect the new requirements.

Product Labeling:

5.  Are existing soil fumigant products being re-labeled and how long can old product labeling be used?

The deadline for registrants to sell product with old labeling has passed (December 31, 2010). Registrants must re-label any old product for sale. However, dealers who purchased product with old labeling before the deadline can sell that product until December 31, 2012. Users may buy product from dealers until December 31, 2012 and use the product with old labeling until it is used up.

Regulators should investigate any suspicious use (for example, repackaging or relabeling new product with old labeling) and report their observations to their Enforcement Branch Liaison or the DPR Product Compliance Branch.

6.  When a pest control business (PCB) who is also a registrant performs a fumigation, can they use product with old labeling?

No, PCBs who are registrants cannot use product with old labeling after December 31, 2010.

Supervision of Handlers:

7.  Does the fumigant labeling require the supervising certified applicator to be in line of sight of all handlers on-site?

No, the supervising certified applicator needs to be on-site and in line of sight of the application. The certified applicator must also directly supervise all handlers on-site during the application.

An exception to line-of-sight supervision throughout the application is provided in the labeling for chemigation. For chemigation the certified applicator may leave the application site after set-up, calibration, and the initiation of the chemigation but must return (or delegate a trained handler to return) every two hours until the chemigation is completed to monitor the application.

8.  Who can perform the duties of the supervising certified applicator?

The supervising certified applicator for a fumigation performed by a pest control business must be employed by the business and be licensed in subcategory O. The supervising certified applicator for a fumigation performed by a grower/permittee must be a certified private applicator (there are no categories for private applicators) or have a qualified applicator license (QAL) or a qualified applicator certificate (QAC) in subcategory O.

9.  Can the tractor driver be the certified applicator? Would this cover supervision of handlers?

Yes, a tractor driver that is a certified applicator may supervise the application. However, the CAC must evaluate the driver’s ability to maintain line of sight with the application and directly supervise all handlers. In this case, the tractor driver would be the supervising certified applicator that verified and signed the fumigant management plan (FMP) and the post application summary (PAS).

The CAC inspector should evaluate the driver’s ability to directly supervise and communicate with all handlers. This could include the use of rearview or side mirrors or other devices to maintain line of sight.

10.  Can you change certified applicators during an application?

No, the supervising certified applicator who verified and signed the FMP must supervise the entire application. In the case of a legitimate emergency, the supervising certified applicator could turn supervision over to another certified applicator but the nature of the emergency and the ability of the substitute supervisor must be documented in the PAS and both supervisor’s must sign the PAS. Scheduling issues would not be considered an emergency.

11.  Does a certified applicator need to supervise tarp removal or other post-application activities?

No, after the application is complete the certified applicator must communicate to the owner/operator and the handlers responsible for carrying out the post application activities the information necessary to comply with the label and procedures described in the FMP.

The communication, as well as the post application activities must be documented in the FMP. The certified applicator must verify in the FMP that the persons performing post application activities have the competencies, facilities, and equipment to perform these activities. The certified applicator must also sign and verify in the PAS all required information regarding post application activities.

Handler Training:

12.  Who is allowed in the application block and buffer zone during the entry restricted period (ERP)? Can a trained handler enter a treated field during the ERP to perform irrigator tasks?

Only trained handlers performing labeling described tasks with appropriate PPE are allowed in the treatment area during the application and the ERP. The labeling includes installing, repairing, operating or removing irrigation equipment in the fumigant application block from the start of the application until the end of the ERP as a handler task.

Only trained handlers performing labeling described tasks with appropriate PPE, and other persons transiting (likely without PPE), are allowed in the buffer zone.

13.  Does the certified applicator need to provide handlers with both U.S. EPA and registrant-prepared safe handling information?

No, the certified applicator needs to provide the information on fumigant safe handling from either the registrant or from U.S. EPA.

14.  Should the labeling required fumigant safe handling information be incorporated into the annual handler training required by Title 3, California Code of Regulations (3CCR) section 6724?

The labeling required Fumigant Safe Handling information must be provided to fumigant handlers every 12 months (as does 3CCR section 6724 handler training). An employer with fumigant handler employees needs to provide both the labeling referenced Fumigant Safe Handling information and the regulatory required training once per year, therefore providing the label required information during the annual handler training would be acceptable.

The labeling and the regulations do not require or prohibit that both of these training requirements be provided simultaneously. The inspector should evaluate the employer’s written training program and determine that the handler has received the labeling required information either as part of the annual training or separately.

15.  Who is in violation if the registrant training is not provided?

If the registrant training is not provided, the certified applicator supervising the application is in violation of conflict with registered labeling (FAC section 12973). Enforcement action would be taken against the applicator’s employer.

16.  If the grower is participating as a handler, is he/she exempt from receiving the labeling required fumigant safe handling information?

No, when the grower performs handler tasks, the grower would need to have received the registrant or the U.S. EPA provided information on fumigant safe handling.

Tarp Removal:

17.  Can field workers remove tarps after the entry restricted period (ERP) has ended?

Labeling allows field workers to remove tarps 14 days after the application has been completed. However, California requirements for certain methyl bromide and chloropicrin applications are as follows:

Regulations for all methyl bromide tarped application methods and some chloropicrin tarped application methods state that the restricted entry interval (REI) does not expire until the tarps are removed. For these applications only handlers can remove tarps.

3CCR section 6447.3 describes the allowed methods for methyl bromide soil fumigations. For those tarped methods, the restricted entry period (REI) does not end until the tarp is removed, unless the tarp will remain in place throughout the planting process.

3CCR section 6449.1(b) restricts the application methods for 100% chloropicrin fumigations to the methods described in sections 6447.3 and 6448.1 in non-attainment areas (NAA) from May 1 through October 31. Since 3CCR section 6448.1 does not address the REI, only fumigations of 100% chloropicrin using section 6447.3 tarped methods in NAA from May through October require the REI to be in place until the tarps are removed. For other chloropicrin fumigations, fieldworkers could remove tarps 14 days after the application is completed.

In all cases, tarps that have been in place throughout the growing season may be removed by fieldworkers.

Fumigant Management Plan (FMP) and Post Application Summary (PAS):

18.  Who is responsible for signing the FMP and the PAS?

Anyone can prepare the FMP but only the certified applicator supervising the application is responsible for verifying all of the information in, and signing the FMP. The labeling states that the certified applicator supervising the application must complete and sign the PAS.

19.  The FMP and the PAS are required by the new labeling. How will the FMP and PAS be enforced

The FMP should be evaluated as part of the field fumigation use monitoring inspection, violations should be documented in Requirement 10, "Labeling - Site/Rate/Buffers/Other" (FAC 12973). The PAS should be evaluated during headquarter and Employee Safety inspections on both permittees and pest control businesses, violations should be documented using a blank line at the end of the Requirements section as violations of FAC section 12973 (use in conflict with labeling). The nature and circumstances of these violations must be explained in the Remarks section.

20.  An inspector documents that a FMP is inaccurate and/or incomplete. For example, the supervising certified applicator failed to sign the FMP or the FMP states that residue from the previous crop will be worked into the soil and allowed to decompose prior to the fumigation but you observe substantial crop residue on the soil surface. Is this a violation? What is the citable section?

Both of these examples represent violations of FAC section 12973, use in conflict with registered labeling. The supervising certified applicator would be in violation in both examples. The FMP must reflect current conditions that are verified by the supervising certified applicator. The supervising certified applicator must also sign the FMP before the application begins.

FMP and PAS labeling requirements are the responsibility of the supervising certified applicator. However, either of these documents could also provide documentary evidence of violations of the labeling, permit conditions or laws and regulations. The evidence of violations and the determination of who is responsible would need to be evaluated. In the second example above, the FMP states that the field has been cleaned of residue in contradiction of direct observation. If the FMP was signed, the supervising certified applicator is in violation for providing false information in the FMP. This would be a violation of the FMP portion of the labeling. (FAC section 12973)

If the applicator initiated the fumigation, the applicator would also be in violation of the mandatory Good Agricultural Practice (GAP) portion of the labeling and, possibly, the permit conditions. (FAC section 12973) The permittee may also be in violation if the permit conditions required proper soil preparation. If that were the case, it would also be a violation, by the permittee, of FAC section 12973, use in conflict with the permit.

21.  Can the applicator or owner/operator legally do something that is in violation of the labeling, permit conditions or regulation if they document that action in the post application summary?


22.  Can the owner/operator provide the certified private applicator supervising a fumigation performed by a pest control business?

No, a pest control business performing soil fumigations must have their own qualified certified applicator employee supervising the application. (See 3CCR section 6445.5)

23.  How can the supervising certified applicator be held responsible for the FMP’s post-application summary if they are no longer in the area of the application (most applicators move around the county or state to make more applications) and when other handlers (e.g., the grower or tarp cutters/removers) are then performing the post application activities?

The supervising certified applicator must communicate to the owner/operator and to the handlers who are carrying out the post application activities the information necessary to comply with the label and procedures described in the FMP (see Supervision of Handlers). Post-application activities may be performed by the grower. However, the labeling requires that the PAS be completed and signed by the supervising certified applicator. The applicator may do this based on information from the grower. Also, the supervising certified applicator does not need to wait 30 days to complete the PAS, all of the information needed for the PAS is available by the end of the ERP. Some of the information needed in the PAS is collected during the application. (See Question 11 for more information on applicator responsibilities.)

The fact that the supervising certified applicator is responsible for the information in the PAS does not exempt the grower from his/her responsibilities to perform post application activities as required by the labeling and/or permit conditions.

24.  When a PCB supervising certified applicator uses the property owner’s employees as handlers, does the property owner need to complete a separate FMP?

No, there can be only one FMP per fumigation. The FMP should identify the property owner’s handlers that will be on site. The supervising certified applicator must also verify that the handlers have been properly trained and equipped.

25.  If the application site is broken into separate blocks, do the post- application summary forms need to be completed on the same date?

The FMP and PAS are block-specific. Each block would have a FMP and a PAS. The PAS must be completed within 30 days after the application is completed to the block. The supervising certified applicator fumigating multiple blocks may format the FMP in a manner that captures information common to all blocks only once. Information unique to a block must be provided in the block-specific FMP.

26.  Does the FMP take the place of the Work Site Plan (required 7-days before a methyl bromide application NOI is submitted)?


27.  How is the FMP provided to Emergency Response Personnel?

The labeling requires that the FMP be provided immediately to emergency personnel when requested. The FMP should state how this will be done under the Emergency Procedures section.

28.  On the FMP, how specific does the evacuation route need to be for each site? Do they need more than is currently required by 3CCR section 6780(d)? Can it simply say - "If evacuation is necessary move upwind to the nearest road."?

The evacuation route must be adequate for handlers to be protected. The direction above would not be useful if there were barriers (fence, wall, canal etc.) to moving upwind or if there was no wind or the wind was variable. It would also be inadequate if the nearest road was in the buffer zone. The CAC should evaluate the emergency procedures, along with all of the information in the FMP based on their knowledge of the hazards of the fumigant and of local conditions.

29.  When completing the Description of all other good agricultural practices portion of the FMP, can the certified applicator simply say “See attached label.”, and attach that portion of the label?

No, in most cases the labeling is too general (i.e. it provides parameters or options on how to achieve the desired condition such as proper soil moisture or tillage). The FMP should state what was done on the specific block to achieve these conditions. Where appropriate, the labeling can be referenced. For example when describing the soil moisture determination, you could say, "soil moisture was determined at 9 inches below the surface using the Feel and Appearance method described in labeling and found to be 50 -75% of field capacity."

30.  For a nursery fumigation of 0.75 acres, using 98% methyl bromide at 200 pounds/acre and applying with the hot gas method, would the applicator be exempt from developing a FMP and reporting the field fumigant method codes on the pesticide use reports?

No, labeling requires a FMP and a PAS for all methyl bromide soil fumigations. The field fumigant method code to use in this situation is 1109 (hot gas). 3CCR section 6447 exempts raised tarpaulin (not hot gas) fumigations of less than one acre from the provisions of sections 6447 through 6447.3 and section 6784(b). The fumigation code for a raised tarpaulin fumigation in this scenario would be 1190 (other label method for MeBr). See the Field Fumigation Method Codes for Pesticide Use Reporting document (Tab 9 in the Soil Fumigation Training manual).

31.  How is the tarp lot number (required on the FMP) accounted for if it can’t be found or is unknown?

The fact that the supervising certified applicator does not know and is unable to find out what the tarp lot number is and why the lot number is unknown must be documented in the FMP.

32.  Is the FMP and/or the PAS required to be in any language other than English?


33A (formerly question 33).  What components of the weather forecast are expected to be included in the FMP? What weather service has detailed forecasts that include inversions?

The labeling identifies the weather factors that that should be evaluated. The labeling also identifies how to obtain forecasts. The most significant conditions to be avoided are shallow, compressed (low-level) temperature inversions and air stagnation advisories. The labeling also identifies where forecasts can be obtained: or your local National Weather Service Forecasting Office.

33B (added question).  Can applicators use the checkboxes on the California FMP template instead of keeping certain documentation in the FMP on-site as required by product labeling?

Yes, the California template allows the supervising certified applicator to use check boxes for some information that is kept off-site. The applicator must verify that the specified documentation is available to regulators, emergency personnel and handlers.

The use of these check boxes was approved by U.S.EPA as part of the Department's discussions with EPA. All of the information required by labeling regarding FMP instructions is required to be kept by applicators. An agreement was reached allowing that some of the information need not be kept on-site in the FMP. This allowance recognizes that some of the documentation outlined in the labeling was already required by the California system (i.e. annual training records and a written respiratory program).

Additionally, CACs have a great deal of flexibility in the permitting system and can require that this information be attached to the FMP as a permit condition if necessary.

Stop-Work Triggers:

34.  If the inspector experiences sensory irritation but the handlers don’t, does that create a stop-work trigger?

No, the stop-work provision is triggered when a handler experiences sensory irritation. An inspector experiencing sensory irritation should move to an area where no irritation is experienced. It would be appropriate for the inspector to investigate the circumstances. If equipped, the inspector could perform air-monitoring. If not, the inspector could request the applicator to perform air monitoring.

35.  Where is sampling done if sensory irritation does occur?

Air monitoring samples must be collected within a 5 foot radius of where the irritation is first experienced within a 10- inch radius of the handler’s nose and mouth (approximately 5 feet from the soil surface).

36.  When sensory irritation is experienced and air monitoring is triggered, does the person performing the air-monitoring require protection from exposure to the fumigant?

Labeling requires that the air monitoring be performed by a trained handler wearing appropriate respiratory protection and PPE.

37.  Does labeling require that air monitoring equipment be on-site before beginning an application?

The labeling does not state that air monitoring devices must be at the site prior to beginning an application. However, if a stop work trigger is activated and no air-monitoring device is available, then the application must cease for the rest of that day or until air monitoring can be performed as required.

Respiratory Protection:

38.  The labeling requires that employees who will wear respirators be examined by a licensed health care professional. Is this any different then the regulatory requirement in 3CCR section 6739(d) that requires that these employees be medically evaluated?

No, these requirements are the same, and full compliance with 3CCR section 6739 [unless exempted by 6739(b)] is required.

39.  Which fumigants require a Self-Contained-Breathing Apparatus (SCBA) onsite?

Products containing chloropicrin, methyl bromide or methyl iodide require that one emergency use SCBA be on site. See 3CCR section 6739(i) for location, placard and inspection requirements for emergency-use respirators. These product labels also require that at least two trained, fit-tested, and medically evaluated handlers with two appropriate respirators be on-site. However, compliance with 3CCR section 6739 [the full respiratory protection program; unless exempted by 6739(b)] is required for all labeling respirator provisions.

Note that metam sodium, metam potassium and dazomet products require that there be at least one trained, fit-tested, and medically evaluated handler on-site with an appropriate respirator. Again, compliance with the full respiratory protection program (3 CCR 6739) is required in California.

Methyl Bromide

40.  Can methyl bromide (MeBr) regulations be more stringent than the label?

Yes. For example, 3CCR section 6784(b)(3) requires the use of half-face, full-face or hood-style respirators for all MeBr field fumigations (with limited exemptions pursuant to Table 2). However, the new labeling requires the use of half-face, full-face, or hood-style respirators only for MeBr products with formulations of more than 80% MeBr, unless a stop-work trigger occurs. For example, handlers applying a 50/50 MeBr product would need to wear an appropriate respirator even when there has been no stop-work trigger event.

41.  For MeBr regulation 3CCR 6784 (b)(3) Table 2, handlers are allowed to work for a limited number of hours for a maximum of three workdays per calendar month without using a respirator. Some applications are made the last 3 days of one calendar month and continue into next calendar month for 3 more days (6-days). Isn’t this a violation of these regulations?

No, handlers can work three days per calendar month. This can result in a handler working as many as 6 consecutive days.

42.  For formulations with greater than 80% MeBr, handlers begin work wearing a respirator. Is it correct that the handler does not have to follow the work hour limitations in Table 1 [3CCR section 6784(b)(3)] because a respirator is being required by labeling and not by regulation?

No, Table 1 requires the use of a half-face respirator. The handler is only exempt from the work hour limitations in Table 1 when using a full-face respirator during the listed activity.

43.  For formulations with less than 80% MeBr, if there is sensory irritation handlers must wear a respirator and monitor the air every two hours. Is it correct that if a handler is wearing a half-face respirator because of the DPR regulation [Table 1 in 3CCR 6784 (b)(3)(A)(1)], then air monitoring would only be required when the handler experiences sensory irritation?

That is correct. In order to harmonize federal labeling with California regulations, U.S.EPA and the Department have agreed that the labeling statement, "When air-purifying respirators are worn, air monitoring samples must be collected at least every two hours...", will be interpreted and enforced as if the statement read, "When air-purifying respirators are required to be worn by this labeling, air monitoring samples must be collected at least every two hours...". This interpretation will only be used when half-face respirators are worn to comply with 3CCR section 6784 (b)(3)(A)(1) since this would allow handlers to experience sensory irritation when fumigant levels rise. When handlers begin the application wearing full-face or hood-style respirators, the labeling required air-monitoring is required as soon as the application begins.

44.  For formulations with greater than 80% MeBr, handlers begin work wearing a respirator. Is it correct that exceptions 1 and 2 to Table 1 would not apply since tarp-cutting and removal are considered handling activities according to the label?

That is correct. The labeling states, “Air-purifying respirators must be worn during all handler tasks…". Tarp cutting and removal are identified in the labeling as handler tasks, therefore respiratory protection is required.

45.  Is it correct that the Table 2 work hour limitations would not apply to formulations with greater than 80% MeBr because respirators are required by labeling at the beginning of the handling activity?

That is correct; product labeling for formulations with greater than 80% MeBr require respiratory protection for all handler tasks.

46.  MeBr work hour limitations - If an employee starts off working without a respirator and then switches to using a respirator how many hours can they work? Do you try to pro-rate the hours or revert to the lowest number of hours?

6784(3)(c) states that no employee shall be allowed to alternate between the workday and work-hour requirements in (b)(3)(A) which refers to Table 1, and (B) which refers to Table 2, unless the employee did not perform fumigation-handling activities during the previous 30 days. When a handler begins work without a respirator, that handler can only work the number of hours allowed for the task being performed. Once the handler has worked the maximum hours allowed, s/he cannot perform additional fumigation tasks until the next day.

47.  Labeling requires different sets of PPE based on tasks with liquid contact potential. What tasks are considered as having liquid contact potential?

The following fumigation tasks have liquid contact potential: connection/detachment of regulators or hoses to fumigant tanks, initial connection and testing of transfer line integrity, contaminated equipment calibration or adjustment, contaminated equipment clean-up, repair of containment equipment such as repair of irrigation system when the system is contaminated or contains fumigant, product sampling, spill clean-up, rinsate disposal and use of a probe in tree hole fumigations.


48.  Do 1,3-D product labels carry these new labeling requirements?

1,3-D products will only carry the new labeling requirements if the product contains chloropicrin.

Methyl Iodide

49.  Can buffer zones on MeI labels extend onto highways?

No, labeling states, “Buffer zones shall not extend onto public roads or areas, or onto any other land for which written consent is not attainable.”

50.  The current Midas labeling states, “All persons working with this fumigant must be knowledgeable about the hazards and trained in the use of required air-purifying respirator equipment and detector devices, emergency procedures and proper use of the fumigant.” Does this mean that shovelers must be trained in how to use detector devices?

This is a general training requirement, all handlers must know what detector devices are and that air -monitoring is conducted in certain circumstances to determine the type of respirator that must be worn and to determine when handlers must leave the application block and buffer zone.

Recommended Permit Conditions for MITC-generating Soil Fumigants

MITC Wind Monitoring

51.  There is a requirement to monitor wind for 12 hours after the application. Is there a requirement for air monitoring during the application?

Yes, permit conditions require wind speed and direction be monitored every hour from the start of the application until the application is complete. For 12 hours after the application is completed, wind speed and direction must be monitored every two hours in a standard area and every hour in a sensitive area.

MITC Buffer Zones (BZ) and Post Application Water Treatments (PAWT)

52.  Do you always need to get permission from an agricultural property even if there is no structure? Do you need to get permission if the buffer zone (BZ) extends into empty real estate i.e. a large parcel on which there is a structure?

Yes, permission is required whenever a BZ extends onto an agricultural property, or a non-agricultural property that contains a structure or a bystander area not owned or controlled by the permittee. Documentation of this agreement must be submitted with the NOI. When the BZ extends onto an agricultural property the permittee must also submit documentation explaining how the operator of the adjoining property will keep fieldworkers from entering the BZ

53.  Can pedestrians transit through buffer zones established in the recommended permit?

Yes, pedestrian and vehicular transit is allowed under current permit conditions, however, when phase 2 federal labeling is implemented pedestrian traffic will be prohibited by that labeling.

54.  If the operator of the property has a written agreement for the buffer zone to extend into neighboring properties and someone violates the buffer zone, who is responsible? Is there a violation?

Preventing unauthorized persons from being in a buffer zone (other that transit) is the responsibility of the supervising certified applicator during the application and the permittee during the post application ERP. Both parties are responsible for using appropriate means to manage the buffer zone. When violations occur, the CAC should evaluate the relevant portion of the FMP (verified by the certified applicator) and permit provisions to determine if appropriate measures were taken. For example, was the perimeter clearly defined and was communication with the neighbor adequate? Enforcement action could be taken against the applicator, the grower or both as warranted.

55.  Why are buffer zone distances reduced for three PAWTs? The addition of more water shouldn’t affect the distance, only the duration.

PAWTs reduce the rate of fumigant emissions. Emission rates determine the size of the buffer zones.

56.  How does water affect buffer zones for nighttime application?

For 1 a.m. starts, Buffer Zone Table 1 is used when there are three PAWTs, Buffer Zone Table 2 is used when two PAWTs are applied.

57.  Some operations use sprinkler set ups that can be accessed remotely. Can monitoring required for Metam or Dazomet PAWTs be done remotely (electronically) and without human evaluation?

No, unless the grower or applicator can remotely monitor changes that could result in off-site movement such as changes in wind speed or direction. The grower or applicator would also need to be able respond to these changes and prevent or reduce offsite movement.

58.  Metam Method 8 - Spray Blade with Soil Cap does not require post application water treatment but requires that the applicator have water available. What does this mean and how does an inspector verify compliance with this requirement?

This is an emergency measure that applies to applications in a sensitive area or that are within ½ mile of an occupied structure. In the event that off-site movement of MITC is detected, the permittee must be prepared to apply a PAWT or apply untreated soil. This requirement is in place for 48 hours from the completion of the application and the permittee must be capable of delivering 0.2 - 0.4 inches of water in 2 to 3 hours over the entire treated site. The inspector should verify that sufficient water and the equipment necessary to deliver the water to the treated area are on-site.

59.   When using the buffer zone tables - what is the conversion formula for calculating the lbs. active ingredient per acre from the gallons per acre?

The lbs. per gallon of pesticide is provided in the active ingredient (a.i.) section of the labeling. For example, one gallon of Vapam HL contains 4.26 lbs of active ingredient. An application of 50 gallons per acre would apply 213 lbs active ingredient per acre. Multiply the lbs of active ingredient per gallon of product by the number of gallons per acre. (lbs a.i. per gallon) X (gallons per acre) = lbs per acre.

60.  There are soil types that will not be able to absorb the amount of water required by the recommended permit conditions without the risk of runoff or erosion. In these situations, is there an alternative to the required PAWTs?

This is the reason that the 0.20 - 0.40 inch range was included, to allow the CAC to determine the amount of water required, based on soil type and moisture content, and air and soil temperature at the time of application. This should addressed by the CAC at permit issuance when the NOI is submitted.

61.  The buffer zone tables list 320 pounds a.i. per acre as the maximum application rate. Metam potassium labels allow a maximum of 360 pounds a.i. per acre. Can this maximum rate be allowed? If so, what buffer zone would be used?

Yes, the maximum application rate for metam potassium of 360 pounds active ingredient per acre (lbs a.i./acre) as specified on the label is allowed. The buffer zone distance for Drip, Spray Blade with Soil Cap and Power Mulcher/Rotary Tiller application methods is set is at 90 feet. The buffer zone distance for metam potassium using other methods should be calculated as follows:

-Use the appropriate Buffer Zone Table in the recommended permit conditions depending on the application method and the number of post-application water treatments

-At rates less than or equal to 320 lbs active ingredient per acre, determine the buffer zone distance (intersection of “application rate” and “acres treated”) then multiply by 0.9. This will allow a shorter BZ distance for metam potassium than for metam sodium.

-At rates greater than 320 and up to 360 lbs active ingredient per acre, simply use the BZ distance at the intersection of the 320 lbs active ingredient per acre column and the appropriate acres treated column.

These reduced BZ distances are allowed because metam potassium generates less MITC than does metam sodium at the same lbs active ingredient per acre.

If you have questions about the current requirements, please contact the Enforcement Branch Liaison assigned to your county, or reference the DPR Fumigant Resource website.

Original Signature by: Original Signature by:
Nan Gorder, Ph.D.
Chief, Enforcement Branch
Sue Edmiston
Chief, Worker Health and Safety Branch

cc:   Mr. Thomas Babb, DPR Agricultural Commissioner Liaison
        Enforcement Branch Liaisons

1001 I Street  ·   P.O. Box 4015  ·  Sacramento, California 95812-4015  ·
A Department of the California Environmental Protection Agency