The USEPA-required phase 2 restrictions for soil fumigants must be
on labels released by registrants for sale on or after December 1, 2012. After that date,
product registrants may only sell, distribute, or use product with the new label. In
contrast, pest control dealers or end users who are not registrants may continue to sell or
use their existing stocks of product with previously-approved labels. Therefore, there
may be both old and new labeling used in the field.
DPR staff have compared the new label requirements to current California regulatory
requirements and to DPR recommended permit conditions for restricted materials. Many of
the requirements supersede or conflict with each other.
This complex comparison task has resulted in the following enforcement determinations
and recommended permit conditions.
This March 2013 letter replaces the December 2012 version by revising recommended
permit conditions regarding minimum buffer zones, isolation of application blocks,
overlapping buffer zones, tarp perforation and removal, and combined work site plans and
Fumigation Management Plans (FMP).
The following are DPR recommended permit conditions for all soil fumigants:
- The most restrictive requirement, whether it is the label, regulations, or
local CAC's adopted permit conditions, must be followed. DPR may provide
specific guidance about exceptions.
- The CAC has discretion to adopt county-specific permit conditions based on
local circumstances and mitigation measure that have worked for them in the past.
- These interim permit conditions may be further refined before final mitigation
measures are determined.
- If buffer zones for two or more applications overlap during the first 36 hours,
the combined acreage of the application blocks must not exceed 40 acres, and in some
cases buffer zone sizes must be recalculated.
- The tarp usage buffer zone reduction credits specified on the label are
allowed. Likewise, DPR recommends allowing buffer zone reduction credits for post-
application water seals, when such credits are specified on product labeling. The
exception is methyl bromide, for which none of the label buffer zone reduction credits
may be used.
- DPR has concerns with enforceability of the label buffer zone reduction credits
for clay content and organic matter percentage. Soil texture can vary within a field,
and it could be difficult for an inspector to verify values reported by an applicator.
Further, DPR is still evaluating whether or not other label reductions, such as soil
temperature, Symmetry rig applications, or the use of potassium thiosulfate are
supported. Therefore, DPR recommends that you not allow buffer zone
reduction credits for these.
- There is a registrant based training requirement on the new labeling. Holders of a
Private Applicator Certificate who will supervise an application under the new
labeling must take the additional registrant based training available at
Holders of a California Qualified Applicator License (QAL) or Certificate (QAC) in
Subcategory O (Field Fumigation Pest Control) do not need to take the
registrant training. U.S. EPA has approved California as a state with a certification
and licensing program (Subcategory O) that meets labeling requirements for registrant
-supplied safety training. Subcategory O qualified applicators already have
received a hard copy of the Addendum to the Field Fumigation Study Guide, which
explains the new safety requirements included in phase 2 soil fumigant labeling.
Chloropicrin alone and chloropicrin with 1, 3-D:
Use the DPR-recommended permit conditions found in Compendium Volume 3 (attached).
The following are highlights of the new permit conditions for chloropicrin.
- Application block size is limited to 40 acres at one location within a 24 hour
- If buffer zones for two or more application blocks overlap during the first 36
hours, the combined acreage of the application blocks must not exceed 40 acres. In
addition, the buffer zone size is based on the combined acreage,
unless all application blocks use tarps that qualify for 60% buffer zone reduction
- Regardless of credits, buffer zones must be a minimum of 25 feet
for applications using tarps that qualify for 60% reduction in buffer zone size. For
applications that use tarps that do not qualify for 60% buffer zone reduction, or
applications that are untarped, minimum buffer zone size is:
These minimum buffer zone sizes do not apply to certain specified application
- 60 feet for application blocks that are less than or equal to six acres, or
- 100 feet for application blocks larger than six acres, up to the 40 acre
- If allowed by the label, buffer zone reduction credits are allowed for tarp
usage and for post application water treatments only. In contrast, label reduction
credits are not allowed for Symmetry application system, potassium thiosulfate, soil
organic matter or clay content, or soil temperature.
- Perforation of any tarp that qualifies for any percentage buffer zone reduction
credit is, at a minimum, 9 days after treatment.
Methyl bromide with chloropicrin:
Use the DPR-recommended permit conditions found in Compendium Volume 3 (attached),
along with current California regulations. The following are highlights of the new permit
conditions for methyl bromide.
- California methyl bromide regulations require both an inner and an outer buffer
zone. In contrast, the new labels mention only a single buffer zone. DPR is
recommending permit conditions to clarify how label buffer zone requirements apply to
inner and outer buffer zones.
- Note that the labeling refers to compliance with California permits for methyl
bromide buffer zone distances.
- The minimum size of the outer buffer zone is 100 feet, except for applications
that meet all of the following criteria:
For applications that meet all of those criteria, the minimum size of the outer buffer
zone is 60 feet.
- Employ the application method described in 3 CCR section
- Are 10 acres or less, AND
- Have an application rate of 235 pounds or less of methyl bromide active
ingredient per acre.
- The document Methyl Bromide Field Soil Fumigation Buffer Zone Determination has
been revised to reflect the new buffer zones. The new revision includes the
requirement that, if buffer zones for two or more applications overlap during the
first 36 hours, the combined acreage of the application blocks must not exceed 40
acres, and the buffer zone size must be based on the combined acreage. The previous
requirement of ¼ mile separation for an isolated block no longer applies. None of the
buffer zone credits described on product labeling may be used for methyl bromide.
- California regulations and Phase 2 labeling have overlapping but distinct
requirements for notification. To simplify compliance, DPR is recommending permit
conditions for a single, comprehensive notification that covers both regulatory and
- Perforation of any tarp that U.S. EPA has rated as qualifying for any percentage
reduction in buffer zone distance is, at a minimum, 9 days after treatment.
- Commissioners have the option to require submission of only a work site plan
(WSP), or to require submission of a single comprehensive document that covers the
requirements for both the WSP and Fumigation Management Plan (FMP).
Metam sodium/potassium and Dazomet (MITC producing compounds):
Until the DPR-recommended permit conditions found in Compendium Volume 3 can be
updated, the following information is provided:
- Follow the label instructions with some exceptions. That is, for post application
water treatment, application timing, restrictions on method of application, and post
application monitoring criteria, follow the current DPR-recommended permit conditions
in Subsection C.7.2.
- The application block size is limited to 50 acres at one location within a 24 hour
period for drench or sprinkler application and limited to 80 acres for all other
- Regardless of credits, buffer zones must be a minimum of 60 feet for applications
using Totally Impermeable Film (TIF) and must be a minimum of 100 feet for other
applications, except for applications to:
For such applications, follow labeling restrictions, which include a minimum buffer
zone of 25 feet.
- golf courses;
- replant of individual vine or tree-sites (tree holes) less than one
- raised-tarpaulin nursery fumigations of less than one acre
- potting soil; and
- greenhouses and other similar structures.
- If allowed by the label, buffer zone reduction credits are allowed for tarp usage
only. In contrast, label reduction credits are not allowed for Symmetry application
system, potassium thiosulfate, soil organic matter or clay content, or soil
Note that a revised California Fumigation Management Plan (FMP) template for phase 2
labels has been posted on DPR's website at
Note also that none of the permit conditions affect the volatile organic compound
regulations, including the fumigation method requirements. However, some labels may
specify fumigation methods that are more stringent than the volatile organic compound
DPR has completed the soil fumigant phase 2 training sessions for the CACs. Numerous
questions and suggestions are being analyzed and will be addressed in a subsequent
If you have any questions, please contact the Enforcement Branch Liaison assigned to