Document ID: EPA-HQ-OPP-2005-0123-0283
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-05-02T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

	WASHINGTON, D.C. 20460

										OFFICE OF

										PREVENTION, PESTICIDES

										AND TOXIC SUBSTANCES

MEMORANDUM

Date:		April 13, 2007

Subject:	Risk Mitigation Options to Address Handler, Bystander, Reentry
Exposures from Methyl Bromide’s Greenhouse, Residential and Structural
Uses

From:		Steven Weiss, Chemical Review Manager

Special Review Branch, 

Special Review and Reregistration Division (7508P)

Through:	Robert McNally, Chief

Special Review Branch, 

Special Review and Reregistration Division (7508P)

To:		Methyl Bromide Docket (EPA-HQ-OPP-2005-0123)

Background

	The Report of Food Quality Protection Act (FQPA) Tolerance Reassessment
and Risk Management Decision (TRED) for Methyl Bromide and
Reregistration Eligibility Decision (RED) for Methyl Bromide’s
Commodity Uses was completed on August 9, 2006.  The Environmental
Protection Agency (hereafter referred to as EPA or the Agency) is
opening Phase 5 of the Public Participation Process for methyl bromide
other uses in May 2007.  This document outlines the risk management
options that EPA is considering to address acute human inhalation risks
from methyl bromide’s greenhouse, residential, and structural uses. 
EPA seeks public comment on these risk mitigation options, particularly
comments addressing cost, feasibility, and effectiveness.  A separate
document is included in the docket that addresses risk management
options for methyl bromide’s soil uses along with the other soil
fumigants being evaluated by the Agency.

	End-use products for the uses described in this document also contain
varying percentages of chloropicrin.  Risk mitigation for exposure
related to all chloropicrin uses is also being evaluated by the Agency
and will be addressed separately as part of the chloropicrin RED
process.  

Summary of Risks

	A full discussion of the risks to humans associated exposure to methyl
bromide is included in the following documents which can be found on the
federal electronic docket management and comment system located at  
HYPERLINK "http://www.regulations.gov"  http://www.regulations.gov .

Methyl Bromide: Phase 5 Health Effects Division (HED) Human Health Risk
Assessment For Soil, Greenhouse, and Residential/Structural Uses.  PC
Code: 053201, DP Barcode: D337288 (April 10, 2007)

  SEQ CHAPTER \h \r 1 Methyl Bromide: Phase 5 Health Effects Division
(HED) Human Health Risk Assessment For Commodity Uses.  PC Code: 053201,
DP Barcode: D304623 (  SEQ CHAPTER \h \r 1 March 10, 2006)

Addendum To Phase 5 Health Effects Division (HED) Human Health Risk
Assessment For Commodity Uses.  PC Code: 053201, DP Barcode: D304619
(July 12, 2006) 

The Agency’s risk assessments indicate that the primary risk concerns
from methyl bromide’s greenhouse, residential and structural uses
involve the acute exposures experienced by handlers, bystanders, and
person(s) reentering treated areas. Acute risks to bystanders, during
and after fumigations, may be of concern depending on the level of
exposure and toxicity of the fumigant.  MeBr air concentrations that
exceed 1 ppm for an 8 hour time weighted average (TWA) and 0.33 ppm for
a 24-hour TWA exceed the Agency’s level of concern for acute
inhalation exposure.   Exposure depends on a number of factors including
application rate, size of enclosure being fumigated, weather conditions,
leakage of the enclosures, aeration methods, and proximity to the
treated area.  

	

Risk Management Options

	The Agency is soliciting comments on the risk mitigation options
outlined below which are based on the revised risk assessments, 
California Department of Pesticide Regulation (CDPR) guidelines for
fumigants, EPA’s mitigation measure requirements for methyl
bromide’s commodity uses, and input from growers, registrants, and
other stakeholders.  It is the Agency’s intent to develop risk
mitigation measures that are clear, enforceable and that reduce acute
inhalation and other risks for:

Bystanders who live and/or work near fumigation sites;

Handlers involved in the fumigant application; and,

Workers and residents reentering treated areas.

	

	At the same time, the Agency is mindful of the importance of fumigation
to commerce.  Thus, the Agency’s goal is to reduce risk while
carefully weighing the important role a fumigant plays.   For the
mitigation options that follow, please provide comments for the
following general questions, as appropriate and specific questions
listed under each mitigation option:

General Mitigation Option Questions

Which use pattern and geographic regions do your comments address?

What is the feasibility of implementing this option on a national level?

What are the economic costs and impacts associated with this option?

How effectively would this option mitigate acute inhalation and other
risks? 

Are there alternative approaches to this option? If so, please describe
and include the rationale for your alternate approach.

	For any other options you would like to suggest, please answer the
above questions as appropriate.   All comments should be submitted to
the public docket on the web at   HYPERLINK
"http://www.regulations.gov/"  http://www.regulations.gov/ .  When
submitting, please identify the question(s) to which you are responding
and include discussions, explanations, and references where possible.	

	The Agency has identified four mitigation measures that, if required,
would directly reduce potential acute inhalation and other risks
associated with greenhouse, residential, and structural fumigation
applications:   

Buffer zones;

Timing of applications; 

Respiratory protection; and

Reentry-restrictions.	

	In addition, EPA has identified eight mitigation measures that could
affect potential risks indirectly.   These options would facilitate and
ensure compliance, enforcement, and planning of fumigant applications. 
With these measures, the Agency is confident that the measures that
directly reduce risk would achieve their intended purpose.   These
indirect choices include requirements for: 

Site-specific fumigation management plan (FMP); 

Defining the responsible party; 

Certification of FMP; 

Record keeping/reporting/tracking; 

Notification/posting; 

Best Management Practices (BMPs);

Fumigation manual; and 

Stewardship program.

	

Buffer Zones 

General

	Establishing a buffer zone around a treated area is an effective method
for managing the risks from acute inhalation exposure to bystanders. 
The distance between the application site and the bystanders allows
airborne residues to disperse before reaching the bystanders.  The
greater the distance, the greater the potential for residues to
disperse, thus deceasing the likelihood that air concentrations where
bystanders are located will cause acute adverse effects.  EPA’s goal
is to determine distances, or buffer zones, which will adequately
protect bystanders from acute exposures, but which are not so great as
to eliminate benefits of fumigant use. The distance or size of the
buffer zones would be based on several factors that include application
rates, field size, leakage rates of the enclosure, and aeration methods
used. Air dispersion modeling based on these factors can be used to help
determine appropriate buffer zones distances.  

	The Agency is considering requiring treatment and aeration buffer zones
for residential, greenhouse, and structural MeBr uses.  Treatment buffer
zones would begin as soon as MeBr application started and would last
until aeration period was initiated.  The aeration buffer zones would
begin with the start of the aeration period and last until MeBr
concentrations at ventilation discharge points (or within the enclosure)
is 5 ppm or less.  Although the aeration buffer zone may stop at this
point, the aeration period would need to continue until air
concentrations dissipate to levels that are no longer a risk concern. 

Specific Mitigation Option Questions

Please estimate the quantitative impacts of requiring buffer zones set
at the following distances:  10 feet, 10 to 30 feet, 30 to 100 feet, and
greater than 100 feet.

To the extent possible, describe what buffer zone distance is not
feasible.  

Fixed Buffer Zones 

	Fixed buffer zone distances for fumigants and other pesticides have
been used by the Agency in the past.   In this case, the required buffer
zone distances provide limited or no adjustment for rate, enclosure
size, or other site conditions.  One example of a fixed buffer zone is
the furfural fumigant uses in greenhouses.  Buffer zones of 90 feet are
required for greenhouses less than 5,000 sq. ft and 300 feet for buffer
zones for greenhouses greater than 5,000 square feet.   This type of
buffer zone is more easily understood and easier to enforce than the
scenario-based buffer zones.  The Agency believes that the use of fixed
buffer zone distances may be adequate for some scenarios, especially
when worst case buffer distances are workable for fumigators.  However,
it may be difficult to implement fixed buffer zone distances for all
scenarios that are both sufficiently protective and workable.

Scenario-Based Buffer Zones 

	While EPA could establish a nationally uniform buffer zone distance for
all applications, the Agency is considering giving fumigators the
ability to determine buffer zone distances based on relevant site
conditions (application rate, enclosure size, enclosure leakage rate,
and aeration method, etc.).  This mitigation option provides flexibility
and decreases the likelihood of overly restrictive buffers based only on
worst case conditions, or buffers which are not adequately protective. 
Buffer zone look-up tables could be provided to determine required
distances.  However, this flexibility also comes with added complexity
in terms of understanding how to use look-up tables and utilize options
for obtaining smaller buffers, educating fumigators, devising easily
understood labels, and enforcing these label requirements.  

Specific Mitigation Option Questions

If scenario-based buffer zones were required by the Agency, please
provide increments of application rates and enclosure sizes that should
be reflected in buffer zones look-up tables.

Geographic/Site-Specific Buffer Zones 

	The Agency has used air dispersion modeling with empirically-derived
emission data combined with measured meteorological data to help inform
its decision making in determining appropriate buffer zones.  Some
geographical areas of the US may not be reflected in the available
emission and meteorological data sets.  As described in the revised risk
assessments, there is some level of uncertainty when applying the
modeling results to the entire country.  The Agency is considering
allowing site-specific buffer zone distances to be based on the results
of modeling performed using more refined site- or region- specific
conditions (e.g., using local weather data).  This modeling could be
conducted by the fumigator, registrant, grower, or other party according
to detailed guidance provided by EPA.   A fumigation manual is a
possible method for providing guidance on how to perform this modeling. 
 

Minimum Buffer Zones 

	Using both empirical data and computer modeling, the Agency’s risk
assessments show that in some cases target air concentrations will not
be exceeded even without a buffer zone. While the assessments may
indicate instances where no buffer is needed, EPA requests comment on
whether to require a minimum buffer zone for all fumigant uses due to
potential variability in emission rate over the application area and
other factors not accounted for by the computer model.

Occupied Structures

	The Agency is considering allowing buffer zones to contain structures
(e.g. homes or other buildings) that are normally occupied if the
responsible party can temporarily relocate occupants who voluntarily
agree to move during the buffer zone period and take steps to ensure
that no unauthorized persons enter the structure during the buffer zone
period (see section 6.0 for further description of the responsible
party).  

Exemptions  

	The Agency is considering allowing transit activities on streets,
roads, roads within agricultural property, highways, and other similar
sites of travel provided they are not within the minimum buffer zone
distances (as described above in the minimum buffer zone section).   The
Agency believes that persons traveling through buffer zones for short
durations (beyond the minimum buffer) will not exceed the Agency’s
level of concern.

Specific Mitigation Option Questions

Should EPA’s regulatory position allow exemptions in the circumstances
described above?

Are there any additional exemptions that the Agency should consider?

Buffer Zones Extending into Adjoining Properties

	There may be situations where the required buffer zone extends onto
adjacent properties owned by other parties.  If such a situation exists,
the Agency is considering a requirement that the responsible party
receives written permission from the adjacent property owner for the
buffer to extend onto their property and that the responsible party must
verify that there are no locations within the buffer zone where
bystanders are likely to be.

Specific Mitigation Option Questions

What information should be included on a written commitment from
adjacent property owners?

What form should it take?

 Work Activity Restrictions

	Application sites are often located near properties where workers
(i.e., bystanders) are present who are not under the control of the
fumigant applicator, grower (who owns, is leasing, or manages the
application site), or designated responsible party.  EPA believes that
the responsible party must take reasonable steps to ensure that persons
other than authorized handlers involved in the fumigation do not enter
the buffer zone.  If the responsible party cannot ensure that
unauthorized persons do not enter the buffer zone, the responsible party
will be required to post signs identifying the boundary of the buffer
zone.

  Sensitive Sites

	The Agency believes that it may be prudent to require additional
protective measures for schools, child day care facilities, hospitals,
nursing homes, prisons, and other sensitive sites:  for example, a
prohibition on a fumigation application while school is in session
within a certain distance (e.g., half mile) of the application block. 
Sensitive sites differ from occupied areas (e.g. homes and businesses)
in that their occupants cannot readily evacuate in the event of mishap,
are usually present for extended periods of time, and may have increased
sensitivity to adverse health effects (e.g. occupants of nursing homes,
hospitals, etc.) 

Specific Mitigation Option Questions

Are there areas not identified above that should be considered to be
sensitive sites?

Timing of Applications

	Generally, less stable atmospheric conditions occur during the daylight
hours and therefore dissipate the fumigant more rapidly than more stable
night time conditions.  The Agency seeks comments and suggestions on
whether application time restrictions would help ensure that periods of
peak emissions do not coincide with stable atmospheric conditions
occurring at night.

 Respiratory Protection for Occupational Activities

	Revised risk assessments for MeBr identify inhalation hazard levels
(i.e., endpoints and uncertainty factors) for occupational risk
assessment.  The revised risk assessments show risk concerns for several
handler scenarios when no respiratory protection is used.  In some cases
inhalation risks can be mitigated with the use of air purifying
respirators equipped with approved respirator cartridge filters or with
self-contained breathing apparatus (SCBA).  Revised risk assessments do
indicate that even with the use of SCBA, exposure for certain scenarios
exceed the Agency’s level of concern.  EPA is considering requiring
that labels identify appropriate respiratory protection based on
applicable air concentration levels and/or specific work activities. 

	Assigned protection factors (APFs) for respirators are used to
determine the reduction of exposure, and are based on the assumption
that users have been fit tested, medically qualified, and trained (these
are not currently required by the Agency).  

	In order to ensure compliance with respirator requirements specified on
labels,  the Agency is considering requiring that occupational and area
air monitoring be conducted to quantify potential exposures.  Of
particular concern are handlers without respiratory protection working
within the buffer zone area.  Such monitoring would need to utilize
appropriate analytical methods given the concentration of concern.   For
example, monitoring methods would need to have a limit of quantification
(LOQ) that is equal or less than the exposure limit. 

Specific Mitigation Option Questions

To what extent are workers who are currently required to wear
respirators fit-tested, medically qualified, and trained?  Please
specify if fit testing is qualitative or quantitative.

What procedures, if any, should the EPA require to ensure that workers
who are required to wear respirators are fit-tested, medically
qualified, and trained (e.g., recordkeeping)?

Fumigators or growers, please describe what air monitoring is currently
performed during and after each fumigation application. Please also
include measurement method(s) as well as LOQ.

 Reentry Restrictions 

	For residential, structural, and greenhouse uses, the Agency is
considering lengthening current entry-restricted periods until air
concentrations in the treated area decline to levels that will not
exceed the Agency’s level of concern (1 part per million for 8-hour
time weighted average and 0.33 for 24-hour time weighted average.   See
respirator section for additional requirements for handlers.

Residential and Commercial Structures

	Current labels require a minimum 7-day aeration period if
non-mechanical or natural ventilation is used, 72-hour aeration period
if using mechanical aeration capable of 5,000 cubic feet per minute
(cfm) rate is used, and reentry without SCBA only when air
concentrations are less than 3 ppm (measured inside the walls).

Greenhouses

	Current labels prohibit reentry for persons other than handlers for 48
hours, allow reentry of handlers without SCBA only when air
concentrations are less than 5 ppm, and allow reentry by non-handlers
after the aeration period without SCBA only when concentrations are less
than 5 ppm. The label recommends aeration periods of 14 days.

Specific Mitigation Option Questions

What impact, if any would result from extending the current
entry-restricted period for greenhouses, residential, and structural
uses?

Are current air monitoring requirements on labels adequate for ensuring
that exposure after reentry do not exceed 1 ppm for 8-hour TWA and 0.33
for 24-hour TWA?  

 

 Site-specific Fumigation Management Plan (FMP)

	There is risk reduction value in encouraging fumigators to anticipate,
recognize, and evaluate the factors that could lead to bystander
exposures that are of concern.  A valuable supplement to other
requirements is a comprehensive site-specific fumigant management plan. 
FMPs were required by the Agency for methyl bromide’s commodity uses,
and public comments submitted to the docket for this requirement were
generally supportive.  FMPs are also required for the structural
fumigations with phosphine gas.  It should be noted that fumigation
applications are complex operations, and to ensure that all label
requirements are met, EPA believes that an FMP is necessary for adequate
planning, compliance, and enforcement.  A sample of elements that the
Agency believes should be included in a comprehensive FMP was provided
TRED/RED document and is available in the docket.   EPA is considering
applying the same requirements for those FMP elements to residential,
greenhouse, and structural uses. 

	In addition to helping ensure fumigators successfully plan all aspects
of a safe fumigation, FMPs will also likely be a major tool for federal,
state, and local regulators to ensure compliance with labeling and
regulations associated with fumigations (see record keeping section
below).

Specific Mitigation Option Questions

To what extent are fumigators currently using FMPs? 

Should FMPs be required for greenhouse, residential, and structural
uses?

Are there any FMP elements that should be required for greenhouse,
residential, and structural uses that are not listed in the TRED/RED for
commodity uses? 

Responsible Party

	For each fumigation event, the Agency is considering requiring that
there be a clear identification of the party who is responsible for
ensuring compliance with label requirements.  The responsible party and
their applicable duties that may impact their own risk as well as other
handlers, bystanders, and persons re-entering treated areas must be
identified in the FMP. 

Specific Mitigation Option Questions

Should the fumigator/applicator be the responsible party for all aspects
of the fumigant application process in regard to label requirements
including tarp cutting and removal?

What is the impact of allowing the responsible party duties to be shared
among different parties (e.g., fumigator, growers, and other parties)?  

Certification of an FMP

	The Agency is considering requiring that the person supervising the
fumigation, or the responsible party, certify in writing that he/she has
reviewed the FMP and that it addresses all elements required by product
labels, and that all decisions on the fumigation processes, buffer
zones, and PPE are appropriate and protective.  EPA is also considering
allowing state or local governments the option of implementing their own
FMP certification process, or allowing fumigators to either self-certify
or contract a third-party for FMP certification.  The Agency believes
that since most of the states do not have an infrastructure like
California with county agricultural commissioners, this option of
allowing self- or third-party certification becomes an important
compliance assurance tool and can be potentially implemented without
placing the responsibility of reviewing FMPs on states that choose not
to assume that role.

Record Keeping, Reporting, and Tracking

	There are currently no requirements on EPA labels for applicators or
growers to keep records of applications made. However, MeBr fumigant
products are restricted use products (RUPs) and certain records must be
kept. Reporting and tracking of applications as part of a site-specific
FMP could be a major tool for federal, state, and local regulators to
ensure compliance with labeling and regulations associated with
fumigations.

Notification/Posting

	If buffer zones are used, bystanders will need to be informed about the
location and timing of the fumigation to ensure they do not enter areas
designated as part of the buffer zone. Furthermore, EPA believes that
bystanders not involved in the fumigation could take other steps to
protect themselves if they were aware of potential risks associated with
fumigations that are occurring near where they live and work.  This can
be accomplished by posting signs, as well as through other communication
methods (e.g., verbal and/or written notification).  Providing access to
site-specific fumigation management plans (FMPs) is one option that may
be used to convey useful information to potential bystanders.  The
Agency does recognize that some of the information in the FMPs may be
confidential and other information included in the FMPs may not be
useful to neighbors.  EPA believes the critical information that must be
communicated to all bystanders includes:

Location of the application site including address

Fumigant(s) applied including EPA Registration #

Potential symptoms and adverse health effects from exposure

Applicator license number and contact information

Responsible party for all aspects of the fumigation process 

Location of buffer zones 

Date/time for start and stop of buffer zones

Reentry restrictions

Emergency procedures and contacts

Notification of local fire departments and first responders

Specific Mitigation Option Questions

What information not listed above should be provided to potential
bystanders?  Include rationale for providing information.

Who should be notified prior to applications?

When should notification be given?

How often should notification be given?

 Best Management Practices (BMPs)

	The Agency believes requiring BMPs to be included on labels (e.g., site
preparation, sealing enclosures, aeration methods, weather criteria,
etc.) will minimize inhalation and other risks from fumigant
applications.  Several fumigant products already incorporate some of
these measures on their labels.  

Fumigation Manual

	The Agency is considering developing a manual to provide guidance to
fumigators, growers, and other stakeholders on how to conduct
fumigations that are in compliance with EPA labels.  The manual could
potentially include guidance on how to determine buffer zones with
site-specific modeling and monitoring data.   As previously mentioned,
scenario based buffer zones involve some complexity that will require
growers, applicators, and other stakeholders to be adequately educated
on the requirements of the EPA labels.  The Agency is currently
developing a similar manual for MeBr commodity uses. 

Stewardship Program

	The Agency is considering requiring fumigant registrants to conduct a
stewardship program independently or together with the other fumigant
registrants, with the following elements: 

Educational/ training materials in both English and Spanish that are
designed to educate workers regarding work practices that can reduce
exposure to fumigants, including:

Best Management Practices (BMPs) that reduce emissions and minimize
bystander exposure; 

The recognition of symptoms associated with fumigant exposures; and,

How to seek medical attention in the event workers experience such
symptoms.

Development of channels for disseminating these training materials to
workers involved in the application of fumigants or in agricultural work
practices that may result in exposure to fumigants and a means of
certifying applicators periodically (e.g. every 2 years).

A description of how and who will conduct the training.

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