# Presentation: 921483

## PAG MANUAL WORKSHOP

- May 24, 2007
- 39th Annual National Conference on Radiation Control

**Notes:**
Good morning/Good afternoon.  Thank you for coming.  My name is [NAME] and I am with [ORGANIZATION].  Today we’re going to talk about the changes that the Environmental Protection Agency has proposed for its revised Protection Action Guide (PAG) Manual.

Before we get started, I’d like to get a sense of who we have attending today. 
 [IF LESS THAN 20 PARTICIPANTS]  Let’s go around the room and introduce ourselves.  Please give us your name and the organization you are with.
 [IF MORE THAN 20 PARTICIPANTS]  Let’s have a show of hands.  How many are with state or local governments?  How many are with offsite response organizations?  How many are with other federal agencies?

I want to point out the emergency exits in this room and remind everyone that the bathrooms are [ADD LOCATION].   We will be taking several short breaks during the workshop, but feel free to step out if you need to.  I would also ask that you turn off your cell phone ringers and conduct any cell phone business out in the hallway.  Thank you.

## Hidden Slide

**Notes:**
If you quickly look at your handouts, you’ll see some information that we’ll be presenting during the workshop.  These include some comparisons between the 1992 PAG Manual and this year’s draft.  There is also a graphic that has a bit of information on it, and some examples that we’ll go over during the morning.  Please refer back to these handouts during the presentation.  We hope they will serve to reinforce the information on the screen at various points in the discussion.

Any questions about the logistics of the workshop before we get started?

## PAG Workshop Elements

- Introduction
- PAG Update Summary
- Early Phase
- Intermediate Phase
- Drinking Water/Food PAGs
- Late Phase
- Conclusion/Summary

**Notes:**
We are going to go through each part of the draft PAG Manual.  We’ll start by summarizing the proposed changes from 1992 and point out what things are staying the same.  We’ll also review these points during the refresher portion of the workshop as we go through each phase.  At the end, if time permits, we would like to hear your feedback on several issues for which we plan to ask for public comment.  If we don’t have time, these same issues will appear in the Federal Register notice and you can comment at that time.  Your thoughts are very important to us, and I encourage all of you to comment on the draft.

## 1992 EPA PAG Manual

- Included updates and revisions to previous editions
- Based on Federal Guidance Report 11 methodology
- 	 (ICRP 26)
- Promised water and Late Phase PAGs

**Notes:**
EPA was delegated the responsibility for providing guidance to other federal agencies on radiation exposure limits when it was formed in 1970.  In 1982, FEMA regulations governing radiological emergency planning and preparedness required EPA to (1) establish the PAGs, (2) prepare guidance on implementing the PAGs, and (3) develop and promulgate guidance to state and local governments on the preparation of emergency response plans.  The most recent version of the PAG Manual was issued in 1992.  Like earlier versions, the guidance was very nuclear-power-plant–centric. At the time the guidance was written, EPA and others in the emergency response community believed that if PAGs worked for nuclear power plant emergencies, then they would be effective for all nuclear incidents.

The 1992 guidance incorporated a number of updates and revisions based on users’ reactions to earlier versions.  One significant update was to the dose assessment methodology, which was revised to factor in the derived guides and risk coefficients found in Federal Guidance Report Number 11.

However, the 1992  version of the manual still left out important guidance on drinking water and the late phases of an incident.  The agency promised these in subsequent revisions of the manual. 

## 2007 Draft PAG Manual

- Clarifies the use of 1992 PAGs for incidents other than nuclear power plant accidents
- Lowers projected thyroid dose for KI
- Provides drinking water guidance
- Includes guidance for long-term site restoration
- Updates dosimetry from ICRP 26 to ICRP 60

**Notes:**
This is a brief overview of the changes that EPA has made to the draft PAG Manual.  Given the current security environment, we thought it was very important to make the PAGs relevant to all types of nuclear incidents.

We have lowered the projected thyroid dose for the administration of stable iodine based on data from the Chernobyl accident.

The draft manual includes drinking water guidance, as well as long-term site restoration guidance.

Finally, the guide updates the dosimetry from International Commission on Radiological Protection Publication 26 (ICRP 26) used in the 1992 edition to the more recent ICRP 60.

## What is a Protective Action Guide?

- PAG—A **value** against which to compare the **projected dose** to a defined individual from a release of radioactive material at which a specific protective action to reduce or avoid that dose is warranted.
**Projected dose** is a dose that can be averted by protective actions.

**Notes:**
I give you these two definitions so that we have a common understanding of two of the many concepts associated with a protective action guide.  The PAG itself is a valuable aid to state and local authorities making radiation protection decisions during an emergency.  Decision-makers compare estimates of projected dose with the appropriate PAG to determine what actions to take.

## Incident Response Phases

**Early Phase**:  Can last from hours to days until the release has stopped
**Intermediate Phase**:  Can last from a week to months
**Late Phase**:  Can last from months to years

**Notes:**
We divide a nuclear incident into three phases.

The Early Phase can be a matter of hours to several days and ends when the radioactive release ends.  During this time, there will be little or no information available, and protective action decisions may be based on incomplete or inaccurate data.

During the Intermediate Phase, which can last for a number of weeks or months, more data will be available.  It is also likely that protective actions will be more restrictive because they are based on more complete and accurate information.  The cleanup planning process can also begin during this phase.

The Late Phase of an incident is really no longer an emergency response.  Activities shift to long-term recovery and cleanup.

## 1992

Evacuation/Shelter 1-5 rem (10-50 mSv)
KI 25 rem (250 mSv) thyroid dose (adult)
Worker 5, 10, 25+ rem (50, 100, 250+ mSv) 

- 1992
- Evacuation/Shelter 1-5 rem (10-50 mSv)
- KI 25 rem (250 mSv) thyroid dose (adult)
- Worker 5, 10, 25+ rem (50, 100, 250+ mSv)

- Early Phase

- 2007
- Evacuation/Shelter 1-5 rem (10-50 mSv)
- KI threshold 5 rem (50 mSv) thyroid dose (child)
- Worker 5, 10, 25+ rem (50, 100, 250+ mSv)

**Notes:**
The next few slides summarize the differences between the 1992 PAG Manual and the current draft for each phase of a nuclear incident.  For the Early Phase, the only difference is in terms of the guidance for the administration of potassium iodide.  We have revised our guidance downward from a projected adult thyroid dose level of 25 rem for adults to a projected child thyroid dose level of 5 rem, a simplified implementation of FDA’s age-specific guides.  This new guidance is consistent with the revised FDA guidance issued in 2001.  The FDA based its new dose-level recommendations on a review of the thyroid cancer data from the Chernobyl reactor accident.  

The Chernobyl data are the most comprehensive and reliable data describing the relationship between thyroid radiation dose and the risk of developing thyroid cancer.  Beginning within a week of the Chernobyl accident, the government began making direct measurements of thyroid exposures in hundreds and thousands of people across three republics of the former Soviet Union.  Four years after the accident, scientists began to observe a marked increase in the incidence of thyroid cancer in children and adolescents in Belarus and Ukraine.  

## Intermediate Phase

- 1992
- Relocate population
- ≥ 2 rem (20 mSv) (projected dose)
- Apply dose reduction techniques
- < 2 rem (20 mSv)
- Food (FDA 1982)
- 0.5 rem (50 mSv) annual dose equivalent
- Drinking water
- Promised

- 2007
- Relocate population
- ≥ 2 rem (20 mSv) (projected dose)
- Apply dose reduction techniques
- < 2 rem (20 mSv)
- Food (FDA 1998): Act based on most limiting of
- 0.5 rem (5 mSv) whole body or
- 5 rem (50 mSv) to most exposed organ or tissue
- Drinking water
- 0.5 rem (5 mSv) first year CEDE

**Notes:**
Activities in the Intermediate Phase are intended to reduce or avoid dose to the public, control worker exposures, control the spread of radioactive contamination, and prepare for long-term cleanup operations.  This phase covers doses received in the first year, out to 50 years.  The 2007 draft manual makes two significant changes to the 1992 guidance.  We add both a new food and a drinking water PAG.  The 1992 PAG Manual incorporated the existing FDA guidance published in 1982.  The 1992 guide simply promised a drinking water PAG.   The agency’s current draft addresses each of these key areas.  Once again, the PAG for food is based on guidance from FDA published in 1998.  This guidance provides a threshold dose limit to assist decision-makers in determining whether protective actions need to be taken for food. 

If one of the dose limit thresholds is met, either the 0.5 rem projected dose limit for the whole body or the 5 rem limit to the most exposed organ or tissue, then local decision-makers should consider action to protect an area’s local food sources.  Such action might be covering exposed food products, moving animals to shelter, and providing protected feed and water to animals.  It may also be necessary to place temporary embargoes on food and agricultural products to prevent public consumption of potentially contaminated food.  

## Hidden—Intermediate Phase

**Notes:**
It is important to remember that these dose limits are based on projected dose for the first year of exposure.  

The recommended PAG for drinking water is 0.5 rem committed effective dose equivalent in the first year of exposure.  A committed effective dose equivalent is used because only one pathway, ingestion, is involved.  The drinking water PAG does not apply to all potable water sources.  The Intermediate Phase PAG covers other water uses like swimming and bathing.

If the projected dose is expected to exceed this threshold, then alternate sources of drinking water may be necessary.  It is also possible that water treatment or other actions may help to reduce the radiation doses received from drinking contaminated water.

A key aspect of the drinking water PAG is that it is not intended to set an acceptable level of contamination of water, nor is it intended to serve as a remediation level in water.  This PAG dose is in addition to the primary Intermediate Phase PAG and applies only in an emergency situation.

## FDA Food PAGs

- 1992
- 1982 FDA guidance
- NCRP 39 methodology
- Preventive PAG 0.5 rem whole body and 1.5 rem thyroid
- Emergency PAG 10 times higher, depends on impact
- Dose only, no activity levels provided

- 2007
- 1998 FDA guidance
- ICRP 56 & NRPB methods
- One set of PAGS
- 0.5 rem whole body dose or
- 5 rem to most exposed organ or tissue
- Dose and derived intervention levels (DILs) provided

**Notes:**
NCRP = National Council on Radiation Protection
ICRP = International Commission on Radiological Protection
NRPB = National Radiological Protection Board

This provides a little more detail about the food PAG.  As mentioned before, this PAG is based on guidance from the FDA.  The 1982 guidance, which was the basis for the 1992 PAG Manual, relied on NCRP 39 methodology, which depended on dietary/social costs/impacts.  A "preventative PAG" of 0.5 rem whole body & 1.5 rem thyroid and an "emergency PAG"  of 5 rem whole body & 15 rem thyroid were presented.  Use of the preventative PAG was in cases of low impact and the emergency PAG was to be used if actions result in a high impact.

The current draft PAG Manual is based on the 1998 FDA guidance, used ICRP 56 & NRPB recommendations.  There is one set of PAGs, 0.5 rem committed effective dose equivalent & 5 rem for tissueor organ.  Suggested activity concentrations were derived (called
DILs) for 9 marker radionuclides plus 15 others for informational purposes.

Information in the 2007 draft should make it much easier and quicker to implement the food PAG.

## Drinking Water PAG

- 2007
- Applicable to drinking water from any source
- EPA Safe Drinking Water Act levels after first year
- Doses will be greatly reduced in subsequent years
- “Bridging language” to explain FDA food PAG (includes water) and EPA water PAG relationship

- 1992
- Promised

**Notes:**
Work on the drinking water PAG has been ongoing since 1993, shortly after the existing manual was published.

We believe that the EPA Safe Drinking Water Standards can be met within the first year following the incident, in most cases.  If the drinking water standard cannot be reached within this 1-year timeframe, either by treatment or replacement water supply, a site may apply for a waiver from the limits.

The drinking water PAG also includes language to explain the relationship between the FDA food PAG, which also includes drinking water, and the EPA drinking water PAG.  These two guidelines do overlap in that they both apply to drinking water.  However, the FDA’s food PAG includes the drinking water used in food products, such as sodas and other beverages.  The EPA does not regulate drinking water in this context.  Similarly, the FDA does not regulate the source of the drinking water used in food products.  The EPA food PAG and EPA water PAG are entirely consistent and provide for an adequate level of protection, particularly for those individuals who do not consume a lot of drinking water but who do consume beverages and other food products which include drinking water.

## Application to Terrorist Incidents

- Since 9/11, new threat of radiological terrorism
- DHS vetted the PAG Manual (Early and Intermediate PAGs) for application to RDDs or INDs and identified the need for Late Phase, or recovery, guidance
- Application of PAGs to IND events
- Scope and scale
- Priority on lifesaving and avoidance of acute effects
- Short response timeframe
- Unique fallout decay curve
- Several projects to address the need for unique guidance

**Notes:**
The September 11, 2001, terrorist attacks highlighted the need for the EPA PAG Manual to cover more than just potential incidents at nuclear power plants.  The Department of Homeland Security has scrutinized the PAG Manual in terms of the applicability of the Early and Intermediate Phase PAGs to radiological dispersal devices and improvised nuclear devices.  (A radiological dispersion device (RDD) is also known as a “dirty bomb,” but it does not have to be a bomb.  Other methods of dispersal may be used.  An improvised nuclear device (IND) can be a stolen nuclear weapon from an acknowledged nuclear nation or a home-made device created by either a governmental (non-acknowledged nuclear power) or non-governmental group.)  DHS also noted the gap in the guidance for the Late Phase. 

Improvised nuclear devices have unique characteristics that the PAGs must address.  Among these are the scope and scale of an incident involving an IND.  The priorities for emergency response efforts in an IND event are lifesaving and the avoidance of acute effects; long-term effects are likely to be minimal.  Obviously, the response time will be very short, and emergency responders will have no advance notice.  And lastly, the radiological materials used in these types of devices possess a unique fallout decay curve.

The Federal Family currently has several projects underway to address the need for unique guidance applicable to these types of radiological incidents.

## Hidden Slide

**Notes:**
This brings us to a point in this summary where we can discuss the differences between radiological releases from nuclear power plant incidents and from terrorist incidents, such as an RDD or “dirty bomb”.  While the PAGs in each of the phases, as well as the food and water PAGs, are not different for terrorist or power plant incidents, there are significant differences that will have an impact on the situation in which they are applied.
To bring our workshop discussion to life, we’re going to alternate our examples between various scenarios.  The first is the detonation of a radiological dispersion device that releases a plume of radioactive material, while the another scenario involves a nuclear power plant incident which causes an atmospheric release of radioactive isotopes.
The demographic and geographic areas that are impacted would be somewhat similar; however, the communication efforts and protective actions—especially in the Early Phase—can be quite different, due to the nature of the event, as you might expect.  An RDD event results in an immediate potential exposure situation, with little or no warning.  Evacuation of all population groups in the plume path may not be possible prior to exposure, and emergency response organizations may or may not be as well-equipped or trained as offsite response organizations near nuclear power plants.
On the other hand, in an incident at a nuclear power plant, there may be some time between the first notification of the public that an incident has occurred and the first release of radioactive material from containment.  For example, though there are no “typical” nuclear accidents, the time between the initial system failures at Three Mile Island and the resulting controlled release by venting containment was a period of days.

Also, consider that a nuclear power plant release may occur over a longer period of time and is typically a much larger source term than an RDD.

## Different Scenarios,  Different Sequences

- Intermediate and Late Phase events will be similar for RDD and NPP scenarios.

**Notes:**
This graphic represents that difference in the two types of events.  It is meant only as a generic, non-specific representation of the significant steps in the timeline of an event and the activities that occur in a particular sequence.  

As I just mentioned, it is easy to see here the different sequences related to notification and potential public exposure.  Communication occurs before public exposure in the power plant scenario, while communication FOLLOWS some public exposure in the RDD case.

In both the Intermediate and Late Phases, however, the release has been terminated.  Activities in those phases will be similar for the two different scenarios.

## Late Phase Guidance

- 2007
- DHS RDD/IND Consequence Management Workgroup drafted current guidance (January 3, 2006, *Federal Register* notice)
- All radiological events covered (NPP/RDD/IND)
-  Optimization

- 1992
- Promised

**Notes:**
The Department of Homeland Security’s RDD and IND Consequence Management Workgroup provided EPA with guidance for the Late Phase.  This guidance is based on the radiation protection principle of optimization.

Optimization is based on the general principle that exposure to radiation should be controlled so as to achieve the lowest level reasonably attainable.  The optimization principle is applied on a case-by-case basis, and numerical radiation criteria for cleanup depend on the specific circumstances of the incident.  The PAG Manual provides several “benchmark” criteria that may be considered by a site recovery work group, including those used by the Superfund remedial site cleanup program and the NRC/Agreement States decommissioning programs.

Ultimately, a site recovery work group will need to balance any number of factors that influence cleanup decisions.  Such factors include the size of the area impacted, the type of contamination involved, the type of wastes generated, the economic effects on the area, and the public’s willingness to accept any given solution.

As a reminder, these 1992-2007 comparison slides, the ones that briefly highlight how the elements found in the 2007 Manual are the same—or different—than those in the 1992 Manual, are in your handouts.  I invite you to turn back to the relevant handout page when we discuss the various PAGs later on.

## Early Phase—Introduction

- Early Phase—Introduction

- Detailed description of proposed PAG revisions
- Exposure pathways
- Crude calculation example for downwind dose estimate
- Evacuation and sheltering
- Discuss KI administration
- Emergency worker limits
- DCFs, DRLs
- Calculation example

**Notes:**
We are now going to go through the Early Phase of an incident.  We will describe the protective actions recommended for the Early Phase, including evacuation and sheltering.  We will also discuss the proposed PAG revisions for KI administration in more detail.  Dose limits for emergency workers will also be briefly presented.  We will then examine the use of dose conversion factors and derived response levels in determining projected dose.  Together, we will perform two calculations.  The first will involve estimating the dose downwind of the source.  The second will demonstrate how to use the dose conversion factors and derived response levels to estimate projected dose.  After this material, we will take a short break before diving into the Intermediate Phase.

## Early Phase Initial Responses

- Notification of state and/or local authorities
- Immediate evacuation/sheltering (if necessary) prior to release information or measurements
- Monitoring of releases and exposure rate measurements
- Estimation of dose consequences
- Implementation of protective actions in other areas, if necessary

**Notes:**
This slide shows the initial response steps.  Of course, the first step is notifying state and local authorities.  In the case of a nuclear power plant, provisions for this notification are built into the site’s emergency response plan.  Depending on the type and extent of contamination, local authorities may require immediate evacuation or sheltering of the nearby population before any measurement information is released.  Monitoring of releases will begin, and exposure rate measurements will be made.  Health physicists and other experts will make some preliminary dose estimates.  Again, in the case of a nuclear power plant, these steps may be coordinated between the offsite response organizations and the onsite health physics staff.  These preliminary dose estimates may cause local decision-makers to implement additional protective actions.  

## Early Phase Exposure Pathways

- Direct exposure
- Inhalation

**Notes:**
Two primary pathways exist for radiation exposure to the public in the Early Phase.  As the radioactive plume moves from the incident site across surrounding areas, members of the public may receive direct exposure to radioactive materials.  These materials may be deposited on the skin and clothing.  The extent of direct exposure will depend on the radiation source and the particular conditions of the incident.

A second important pathway is inhalation.  This can occur when members of the public are directly immersed in the plume.  In most cases, the dose from inhalation of radioactive particles is of greater concern than skin or clothing contamination.

Ingestion could be an important pathway, but that is addressed in the Intermediate Phase and food and water PAG sections of the revised manual.

## Establish Exposure Patterns

- In the Early Phase, data are not sufficient to accurately project doses
- Project dose using a combination of data and estimates:
- Initial environmental measurements
- Source term estimates
- Previously observed atmospheric transport under similar meteorological conditions

**Notes:**
The data that you will have access to during the Early Phase will not be sufficient to accurately project doses.  So, many of the decisions that will need to be made during the Early Phase will be based on early data that may or may not portray the true situation.  

But that does not mean decision-makers can afford to wait until better data are available.  Initial estimates of projected dose can be made based on the initial environmental measurements, the preliminary estimates of the source term, including its radiological characteristics, and atmospheric modeling. 

## Simple Exposure Rate Calculation

- D2=D1(R1/R2)y

- If a site-specific model is not available, a simple method can be used to calculate the exposure rate at the plume centerline at ground level (1 m height).

- D1 and D2 are measurements of exposure rates at the centerline of the plume at distances R1 and R2
- y is a constant that depends on atmospheric stability

**Notes:**
Although we prefer to use available computer programs to perform calculations, in the early phase of an accident, it may be difficult to access the necessary computer software.  Therefore, it is essential that everyone knows how to make a crude exposure calculation by hand.  

This very simple equation can be used when a site-specific model is unavailable.  D1 and D2 represent exposure rate measurements at the centerline of the plume at distances of R1 and R2, respectively.  The stability class is represented by y. 

## Calculation Example

- The RDD exploded at 8:30 am (atmospheric stability Class E, winds of approximately 5 miles per hour).  A radiation monitor 100 meters from the blast site recorded fluctuating readings over the first 60 minutes that averaged 500 mR/hr.  What would the estimate of exposure rate be at a distance of 2 kilometers (nearest public school) from the blast location?

- R1	=	100 m
- R2	=	2000 m
- D1	=	500 mR/hr
- y	=	1

- This information should be analyzed in conjunction with plume source-term projections and airborne radioactivity concentrations to determine if evacuation or shelter-in-place is appropriate.

**Notes:**
Here is an example calculation using the previous equation.  We have some early measurement data from an RDD explosion that occurred at 8:30 am.  Winds are approximately 5 miles per hour.  Early measurements from a radiation monitor located 100 meters from the blast average 500 millirem per hour.  To calculate the exposure rate at a distance of 2 kilometers, you would solve for D2.

As you can see, D2 equals 500 (the value for D1) divided by the ratio of R1 to R2 (100 m/2000m) raised to the 1st power.  Remember from the previous slide that the value for y, the stability class for light winds, (that is, those less than 10 miles per hour), is 1.  

Thus, the exposure rate at the nearest public school is 25 millirem per hour.

## Evacuation

- Same as 1992 PAG Manual

- Primary objective is to avoid exposure by moving away from the path of the plume
- Can be 100% effective if completed before plume arrival
- Exposure reduction occurs if evacuation precedes plume passage

**Notes:**
The primary protective actions during the Early Phase are evacuation and/or sheltering.  Neither the recommendations for evacuation nor those for sheltering have changed from the 1992 Manual. In the case of evacuation, the primary objective is to avoid public exposure by evacuating people residing in the path of the plume.  This can include individual residences, office buildings, and schools, depending on the nature and extent of the incident.  Evacuation can be a highly effective protective action, particularly if completed before the arrival of the plume.  

## Sheltering

- Use of readily available, nearby structures
- Sheltering decisions should be based on material released and exposure pathway
- For noble gases, external exposure is the dominant pathway
- Consideration for inhalation pathway
- Ventilation control
- Seal cracks and openings
- Open shelters after plume passage to ventilate

**Notes:**
Sheltering also has the goal of reducing public exposure to the radioactive materials in the plume.  Unlike evacuation, sheltering does not involve moving people away from the plume, but rather shelters them in readily available, nearby structures.  Depending on the type of material released and the exposure pathway, sheltering offers a less disruptive and less expensive option for reducing risk.  It may also be much easier for a local community to implement than an attempt to evacuate all of its residents.  There is very detailed information in the revised manual on this subject.  It is not an easy decision.

In the case of a nuclear power plant incident, the primary pathway of concern will be external exposure to gamma radiation.  Exposures via this pathway can be effectively reduced by sheltering.  Sheltering can also reduce the potential for exposure via the inhalation pathway, if necessary.  The key factors in using sheltering to protect against inhalation of radioactive materials are controlling the ventilation in the structure, reducing the air exchange rate in the structure by sealing cracks and openings, and opening the shelter as soon as the plume has passed to reduce airborne activity that may have become trapped inside the building.  

In some instances, decision-makers may choose to administer potassium iodide as a protective measure against thyroid cancer.  It is the guidance involving the administration of potassium iodide that has changed since EPA’s 1992 PAG Manual.

## Potassium Iodide Actions

- FDA recommendations for Early Phase KI administration is a multi-pronged approach:
- Children 0-18 years:  Projected dose to thyroid is 5 rem (50 mSv) or greater
- Pregnant and lactating women:  Projected dose to thyroid is 5 rem (50 mSv) or greater
- Adults up to 40 years:  Projected dose to thyroid is 10 rem (100 mSv) or greater
- Adults over 40 years:  Projected dose to thyroid is over 500 rem (5 Sv) [preventing hypothyroidism]
- EPA proposes a simplified approach:
- Provide KI to public if 5 rem (50 mSv) child thyroid dose projected
- This is a supplemental action where evacuation is the primary protection

**Notes:**
Using potassium iodide is an effective protective action for situations involving RADIOIODINE RELEASES ONLY, and where evacuation cannot be implemented or exposure occurs during evacuation.  Radioiodine is typically associated with nuclear power plant releases.  The FDA recently updated its guidance on the use of potassium iodide as a thyroid blocking agent.  As this slide shows, the FDA guidance is targeted to specific groups of people, such as pregnant and lactating women, who have projected exposures at varying levels.  For example, children up to the age of 18 should receive KI if the projected dose to the thyroid is 5 rem, but adults over 40 years old should receive KI only if the projected dose is 500 rem—orders of magnitude greater!

EPA felt that it was important to simplify this approach and offers the alternative that KI be given to both children and adults when the projected dose to the thyroid is 5 rem, the lowest intervention level included in the FDA guidance.

This new EPA recommendation represents a reduction in the threshold value for a projected dose to the thyroid from the 25 rem dose level contained in the 1992 guidance. 

## Guidance for Emergency Workers

| Dose (rem) | Activity | Condition |
| --- | --- | --- |
| 	5 | All | None |
| 	10 | Protecting valuable property | Lower dose not practicable |
| 	25 | Lifesaving or protection of large populations | Lower dose not practicable |
| 	>25 | Lifesaving or protection of large populations | Voluntary basis/fully aware of risks |

**Notes:**
EPA’s guidance for emergency workers remains unchanged.  The dose guides for workers performing emergency services, such as firefighters, law enforcement, and health services personnel, are derived using assumptions that differ from those used in developing the PAG for the general population.

One important difference is that these guides apply to doses incurred over the duration of an emergency.  The PAGs consider only the future dose that can be avoided by a specific protective action; these guides include all doses received during an emergency.

If at all possible, doses to emergency workers should be limited to 5 rem.  Higher exposure limits may be justified in the case of protecting valuable property, saving lives, or protecting large populations.  Under rare circumstances, an emergency action may result in radiation doses greater than 25 rem.  Workers undertaking any emergency action in which the dose will exceed 25 rem should do so only on a voluntary basis.  Such workers must also be made fully aware of the risks involved, including the numerical dose levels at which acute radiation effects may occur, as well as numerical estimates of the risk of delayed effects, such as cancer.

Note that the Occupational Safety and Health Administration (OSHA) says that dose should be limited to 5 rem in any case, but this EPA guidance is in keeping with the Presidential Guidance on dose acquired in performing appropriate emergency actions.

## Dose Conversion Factors

- Dose conversion factors (DCFs) are useful for exposure to multiple radionuclides.

-      *H* = Dose
*DCF* = Dose Conversion Factor for radionuclide *i*
-      *C* = Time-integrated concentration of radionuclide *i*

**Notes:**
The current draft of the PAG Manual includes the dose conversion factors and derived response levels for those radionuclides most likely to be released during a nuclear incident.  These values will assist decision-makers in translating measurements of radionuclides given in curies to dose limits given in rem.

Dose conversion factors are most useful when a release involves a number of radionuclides.

## DCP Example

- An accident at an industrial facility resulted in the release of radioactive iodine that was dispersed into the atmosphere.  A populated area outside of the site boundary experienced the following radionuclide concentrations:
- 	2E-8 μCi/cm3	Tm-170	DCP = 3.2E+4
- 	4E-9 μCi/cm3	Cs-134	DCP = 7.6E+4
- 	1E-7 μCi/cm3 	I-131	DCP = 2.7E+4
- (DCF in units of rem-cm3 per h-μCi, Table 2-5 in PAG Manual)

- H 	= (2E-8 x 3.2E+4) + (4E-9 x 7.6E+4)
- 	    + (1E-7 x 2.7E+4)
- 	= _0.004 rem/hr_

- For a four-day exposure period, an evacuation PAG of 1 rem TEDE would not be exceeded.

- 0.004 rem/hr x 96 hours =
- _0.4 rem_

**Notes:**
You’ll notice the title of this slide contains the acronym, DCP.  This is our way of gently exposing new terminology found in the revised manual.  DCP stands for dose conversion PARAMETER.  This is the same as the dose conversion FACTOR, but the term was changed to avoid confusion with other “factors” introduced with the inclusion of Turbo FRMAC methodology. 

So, DCF becomes DCP...Let’s walk through an example.  An accident at an industrial facility results in a release of radioiodine and other radionuclides in the time-integrated concentrations shown here.  Their DCPs are also provided.

The dose rate over the four-day period is 6 millirem per hour, resulting in a total dose of 0.6 rem – not enough to exceed the PAG for evacuation. 

## Conclusion

- Questions or comments on the Early Phase PAGs?

## Break

**Notes:**
We will pause here for another 10-minute break, and this break will also be strictly enforced!

When we return, we will look at the PAGs related to the Intermediate Phase, including the differences found in the new draft revision and some examples.  We’ll see you back here in 10.

## Intermediate Phase—Introduction

- Intermediate Phase—Introduction

- Detailed description of proposed PAG revisions
- Exposure pathways
- Relocation and dose reduction
- Dose projection (with calculation examples)
- External (gamma) exposure
- Internal exposure (inhalation dose)
- Exposure limits
- Longer term objectives for Intermediate Phase PAGs

**Notes:**
Now let’s look at the Intermediate Phase.  As we did before, we’ll go through a discussion of the proposed revisions to the Intermediate Phase PAGs.  This would be a good time to refer to your handouts for the 1992-2007 comparison.  You’ll notice that the PAGs were mostly unchanged in the new version, but we’ll see that the calculations and methods used to project dose have changed.  Exposure pathways in this phase differ from those in the Early Phase, so we’ll talk about issues associated with what these pathways are and how dose to the public via these pathways can be minimized.  As part of this discussion, and because the basis for the dose calculations has changed, we’ll walk through another set of examples to project doses from external and internal exposure.  Finally, we’ll touch upon exposure limits and look at the longer term objectives of the Intermediate Phase PAGs.

## Intermediate Phase

- Period that begins after the source and releases have been brought under control
- Environmental measurements are available as bases for decisions
- May overlap Early and Late Phases
- Exposure pathways are primarily whole body external dose and internal dose from inhalation or ingestion

**Notes:**
The Intermediate Phase begins when the radioactive releases have been controlled.  Unlike the Early Phase, when decisions had to be made quickly and were based on very preliminary data, the information available during this phase will be far better and more complete, and response teams can expect federal assistance to be available.

The Intermediate Phase activities may overlap both the Early and Late Phases and may last from weeks to months.

Exposure pathways are primarily whole body external dose resulting from deposited radioactivity and internal dose associated with the inhalation of radioactive particles.  Doses from ingestion may also be of concern if food and water supplies are contaminated.  Furthermore, in some cases, skin exposure to beta radiation may also present a significant risk, depending on the radionuclides released.

## Protective Actions

| Protective Action Recommendation | PAG
(projected dose) | Comments |
| --- | --- | --- |
| Relocate the general population | ≥ 2 rem (20 mSv)
First year | Beta dose to skin may be up to 50 times higher |
| Apply simple dose reduction techniques | < 2 rem (20 mSv)
First year
 | Reduce doses to as low as practical levels |
| Longer term objectives | 0.5 rem (5 mSv) | In any single year after the first |
|  | ≤ 5 rem (50 mSv) | Cumulative dose over 50 years |

**Notes:**
One of the primary goals during the Intermediate Phase is to protect the public from exposure to radiation from deposited radioactive materials, which is also known as groundshine.  The protective actions you see here, relocation and the application of simple dose reduction techniques, have not changed.  If the projected dose for the first year is greater than 2 rem, local decision-makers should consider relocating affected portions of the population.  If the projected dose is less than 2 rem, dose reduction techniques, such as decontamination, shielding, and exposure time limits, can be used.

The Intermediate Phase PAGs have two longer term objectives.  Protective actions taken should ensure that doses in any single year after the first will not exceed 0.5 rem and that cumulative dose over a 50-year period, which includes the first year, does not exceed 5 rem.  These longer term objectives incorporate actions to protect against both internal and external exposure.

## Response Areas

- Priorities
- Protect all persons from doses that could cause acute health effects
- Establish a strategy for relocation
- Recommend simple decon techniques and spending as much time indoors as possible

- Plume Direction

- Shelter Area

- Evacuation Area

- Deposition Area

- Relocation Area

**Notes:**
People living or working in contaminated areas will need special attention.  It is essential that all persons be protected from radiation doses that could cause acute health effects.  This will likely involve relocation.  Thus, another priority is establishing a relocation strategy to effectively and efficiently remove people from highly contaminated areas.

If the potential exposure rates are not high enough to mandate relocation, people can be instructed on simple decontamination techniques, such as scrubbing and washing surfaces, and advised to spend as much time indoors as possible.

## Sequence of Events

- Identify high dose rate areas
- Relocate population from high dose rate areas
- Allow return of evacuees to noncontaminated areas
- Establish relocation areas
- Establish procedures for reducing exposure of nonrelocated population
- Perform detailed environmental monitoring
- Decontaminate essential facilities and routes
- Begin recovery activities

**Notes:**
Intermediate, as well as Late Phase efforts and activities are similar for both RDD and NPP events.  Several protective actions may be taken over the period of the Intermediate Phase.  The activities presented on this slide are in general sequence but may overlap.  For instance, return of evacuees to noncontaminated areas could coincide with establishing relocation areas.  Environmental monitoring will likely take place throughout the Intermediate Phase.  Establishing the relocation areas may require decontamination of essential routes to allow access.

## Example—Total Dose Due to Deposition

- Example—Total Dose Due to Deposition

**Notes:**
Let’s look at an example calculation of the total dose due to deposition.  This calculation is presented in the manual, and each term in the total dose parameter calculation is described in detail.  It is essentially a sum of two terms—effective dose parameter for inhalation of resuspended material, and the external dose parameter resulting from groundshine.

The effective dose parameter is the committed effective dose received from the inhalation of the resuspended radionuclide i over the time phase under consideration and per unit of radioactivity of radionuclide i deposited on the ground.  The external dose parameter is the groundshine dose received, over the time phase under consideration, per unit of radioactivity of radionuclide i deposited on the ground and adjusted for the ground roughness factor.

Of course, multiple radionuclides can be evaluated, and the total dose parameter (TDP) would be a summation of terms for each radionuclide.

The time phase could be the Early Phase, Year 1, Year 2, or the 0-50 year period.  These terms are also dependent on whether you wish to correct for ground roughness.

So, how are each of these terms calculated?

## External Dose

**Notes:**
The external dose parameter is a calculation that factors in a combined removal parameter and an external dose factor for each specific radionuclide.  

The combined removal parameter is a value that adjusts the external, groundshine dose and incorporates weathering effects which decrease the groundshine dose over the time phase under consideration.

The external dose factor for deposition is the effective dose rate from the external exposure per unit activity deposited on the ground and can be adjusted for the ground roughness factor.

## Inhalation Dose

**Notes:**
The effective dose parameter, the term dealing with inhalation of resuspended radioactive material, includes, as you might expect, a resuspension factor that adjusts the AIRBORNE radioactivity level over the time period of interest.  

The committed dose factor, then, is responsible for dose rate per radioactivity concentration for the volume of inhaled air.  It is the committed effective dose rate from breathing contaminated air.  The resuspension parameter, KP, is a value that adjusts the airborne radioactivity level for radioactive decay and resuspension over the time phase under consideration.  This value is available through the Turbo FRMAC code.

So, let’s put all of this information to use and look at a specific example of how we could determine the total dose due to deposited materials.

## Example:  239Pu or 137Cs in RDD

- Example:  239Pu or 137Cs in RDD

- What are the total dose parameters for the first year for deposited contamination resulting from the scenarios where an RDD has deposited either 239Pu or 137Cs on a populated area (assume weathering)?

**Notes:**
What is the total dose for the first year for deposited contamination resulting from the scenarios where an RDD has deposited either 239Pu or 137Cs on a populated area?  For this example, we will adjust for weathering effects.

First, we will need to determine the total dose parameter, and I am sure you will recall this equation from a few slides back.  The time phase (TP) is 1 year, and we’ll want to take into account weathering over that period, as well as the ground roughness factor.

An interesting comparison is to look at each radionuclide to see the effects of alpha emitters and gamma emitters on the total dose.  So while we work through this example, we’ll take a closer look at what that effect is.

We could calculate each term in the equation separately.  Turbo FRMAC would be a useful tool to help in that calculation.  However, today we will just use Table 3-3 in the revised manual, which has TDPs for several radionuclides and takes into account weathering and ground roughness.

## Comparison of 239Pu and 137Cs 

- Comparison of 239Pu and 137Cs

- 239Pu
- 1st year time phase
- TDP_Dp =
- 6.73E-5 mrem per pCi/m2
- _Initial Dose Rate_
- External Exposure Factor =
- 4.43E-12 mrem/hr per pCi/m2

- 137Cs (with 137Ba)
- 1st year time phase
- TDP_Dp =
- 4.77E-5 mrem per pCi/m2
- _Initial Dose Rate_
- External Exposure Factor =
- 6.01E-9 mrem/hr per pCi/m2

- Initial dose rate corrected for ground roughness factor

**Notes:**
Of course, using the table makes it much simpler.  But the calculations may not be as onerous as they look, since they can be completed using Turbo FRMAC.

As you can see from this comparison, the alpha-emitter and the gamma-emitter, over a period of one year, will result in roughly the same dose per activity concentration deposited.  However, there is a three-fold order of magnitude difference in the initial external dose rate factor.  This difference accentuates the dominance of the inhalation dose for plutonium versus cesium.

Of course, you may have already suspected that from intuition—but it’s nice when the numbers back up that intuition. 

## Total Dose for 239Pu and 137Cs  Examples

- Total Dose for 239Pu and 137Cs  Examples

- 239Pu
- 1st year time phase
- TDP_Dp =
- 6.73E-5 mrem per pCi/m2
- Initial Contamination Level =
- 100 pCi/m2
- Total Dose = 59 mrem

- 137Cs (with 137Ba)
- 1st year time phase
- TDP_Dp =
- 4.77E-5 mrem per pCi/m2
- Initial Contamination Level =
- 100 pCi/m2
- Total Dose = 42 mrem

- PAG recommends dose reduction techniques.

**Notes:**
These total dose parameters can then be used in conjunction with environmental measurements of activity concentrations to estimate total dose and, thus, allow comparison with the PAGs for the Intermediate Phase.

For an adult working and living in a deposition area with 100 pCi per square meter of contamination—that is, conservatively spending 100% of his or her time in that area—the total dose is approximately 59 mrem for the first year in the case of plutonium, and 42 mrem for cesium.

For the first year with a total dose of less than 2 rem, PAG recommends applying dose reduction techniques.  So, in these cases, the population may be allowed to remain in the deposition area, but perhaps they will need to keep their windows closed for the first year—or have their home and grounds thoroughly washed and/or rinsed to reduce contamination levels.

## Applying Relocation PAGs

- Creation of a relocation area may result in:
- Relocation of Early Phase evacuees
- Relocation of persons not previously evacuated
- Return of evacuees who reside outside of the relocation area

**Notes:**
To meet the Intermediate Phase PAGs, it may be necessary to establish a relocation area, which will affect those individuals who live within the boundaries of the area.  The creation of such an area is likely to result in three different actions:

  Those individuals who were evacuated in the Early Phase, but who reside in the relocation area, must be relocated.
  Those individuals who live within the relocation area, but who were not evacuated during the Early Phase, must now be relocated.
  Those individuals who were evacuated during the Early Phase, and who do not live within the relocation area, may return to their homes.

## Surface Contamination Control

- General guidance
- Do not allow monitoring and decontamination to delay evacuation
- If necessary, establish emergency contamination screening stations
- Establish monitoring and personnel decontamination facilities at evacuation centers
- Set up monitoring and decontamination stations at exits from the relocation area
- Establish auxiliary monitoring in low background areas
- Do not waste effort trying to contain contaminated wash water
- Applies to both Early and Intermediate Phases

**Notes:**
Areas over which the plume passed may contain deposited radioactive materials if aerosols or particulate materials were released during the incident.  The primary exposure pathways from loose radioactive contamination are:

  Internal doses from ingestion from direct transfer
  Internal doses from inhalation of resuspended materials
  Beta dose to skin from contaminated skin or clothing or from nearby surfaces
  Dose to the whole body from external gamma radiation

The slide provides the agency’s general guidance for controlling surface contamination both before and after relocation protective actions are implemented—such as setting up monitoring and decontamination stations and establishing auxiliary monitoring in low background areas.  This guidance applies to both the Early and Intermediate Phases.  Tables 3-8 and 3-9 in the draft PAG Manual provide recommended protective actions related to surface contamination based on exposure levels before and after decontamination.  The Centers for Disease Control and Prevention are also developing guidance for contamination control.

## Conclusion

- Questions or comments on the Intermediate Phase PAGs?

**Notes:**
Are there any questions or comments on the Intermediate Phase PAGs?  Let’s move on to the drinking water and food PAGs.

## Drinking Water and Food PAGs

- Relationship of drinking water and food PAGs to Early, Intermediate, and Late Phases
- Drinking water PAGs
- Projecting doses using DRLs
- DRLs for multiple radionuclides
- FDA food PAGs
- Derived Intervention Levels (DILs) (with calculation)

**Notes:**
The drinking water PAG is a new addition to the PAG Manual, and the food PAG has been revised based on updated FDA guidance since the 1992 edition of the manual.

We will look at the relationship of these two PAGs to the Early, Intermediate, and Late Phases.

In reviewing the drinking water PAG, we’ll explain how to project doses using derived response levels and how those levels are applied when the situation involves multiple radionuclides.

Finally, we’ll look at the FDA food PAG and the derived intervention levels.  We will use another calculation to demonstrate how the DIL can be used to determine the need for protective actions.

## Drinking Water PAG

- Drinking water—0.5 rem (5 mSv) first year committed effective dose equivalent
- Applicable to drinking water from any source
- EPA Safe Drinking Water Standards after first year

**Notes:**
You’ve already seen some of this, but since this is an entirely new section of the PAG Manual, it is worth reiterating.

The proposed PAG for drinking water is 0.5 rem projected dose in the first year committed effective dose equivalent.  This dose is expressed as a committed effective dose equivalent because only one pathway, ingestion, is involved.  The PAG applies to all sources of drinking water, but not all potable water sources.  For example, the Intermediate Phase PAGs cover other water uses like swimming and bathing.

EPA’s Safe Drinking Water Standards will kick in after the first year (4 mrem/yr).  If, however, these standards cannot be reached in the first year, a waiver may be requested. 

## Protective Actions for Water

- Wait for flow-by
- Ration clean water supplies
- Treat contaminated water
- Activate existing connections to neighboring systems
- Establish pipeline connections to closest sources/systems
- Import water in tanker trucks
- Import bottled water

**Notes:**
These are the most likely protective actions that a community could take if its drinking water sources were contaminated.  To assist in making this decision, the draft PAG Manual presents relative costs of each of these options, which can then be used to conduct a cost/benefit analysis.  Local water utility experts will be the most knowledgeable about specific requirements and limitations in your area.

## Projecting Drinking Water Doses

- DRLs are concentrations of radionuclides in water that correspond to a PAG of 0.5 rem in the first year (table of DRLs provided in PAG Manual).

- Sum of fractions is used for multiple radionuclides.

**Notes:**
Just as we had to convert measurements of radioactivity in air to dose rates, we must also convert the concentration of radionuclides in water to a dose rate.  This is done by comparing radionuclide concentrations to a derived response level, which incorporates the drinking water PAG of 0.5 rem in the first year.

For a single radionuclide, the concentration must be less than the derived response level, or the PAG will be exceeded.  As the equation here shows, for multiple radionuclides, a sum of fractions will show if the total PAG is exceeded even if individual radionuclide concentrations do not exceed the PAG.

In the PAG manual, DRLs, in units of pCi per liter are provided, and the radionuclide concentration, C, should be in the same units.

Let’s look at an example.

## Drinking Water Example

- Assume that, as a result of a nuclear power plant accident, a water supply is contaminated as follows:
- 131I	100,000 pCi/L	DRL	=	406,504 pCi/L
- 137Cs	12,000 pCi/L	DRL	=	13,850 pCi/L
- 90Sr	3,500 pCi/L	DRL	=	4,950 pCi/L

- F>1, PAG is exceeded

**Notes:**
In the case of a nuclear power plant release, a water supply is contaminated with the following concentrations of iodine, cesium, and strontium shown here.  Using the sum of fractions equation, we see that each term—and thus each radionuclide—does not exceed the PAG on its own.  However, when they are added together, the PAG is exceeded in this case.

## Drinking Water PAGs

- Early Phase
- Public can continue to drink water unless told otherwise
- Intermediate Phase
- PAG based on optimization of cost and risk and consistency with other guidelines
- Late Phase
- Protective actions can reduce dose, if actions are warranted after the first year

**Notes:**
Let’s look at how the drinking water PAG may be applied at each phase of a radiological incident.  During the Early Phase, it is unlikely that emergency responders will be able to determine the full extent of any contamination to surface water bodies.  It is also unlikely that the plume would have contaminated water that was directly available for consumption through the community’s distribution systems.  During the Early Phase, the public can continue to drink water unless told otherwise.

In developing the drinking water PAG, EPA considered the costs and benefits of various control options, consistency with FDA guidance for food ingestion, and the recommendations of the International Commission on Radiological Protection.  EPA set the drinking water PAG at a level that is consistent with both national and international guidance.

During the Late Phase, it may be necessary to continue protective actions initiated earlier.

## Food Dose Projection Resources

- Draft PAG Manual provides radionuclide-specific dose coefficient tables
- Manual provides ICRP values for intake based on age groups
- Manual provides dose coefficient, and DILs reference information from several international organizations

**Notes:**
The draft PAG Manual makes several resources readily available for use in projecting dose.  Among these resources are radionuclide-specific dose coefficient tables, ICRP values for age-based intake, and dose coefficients and DIL values used by several international organizations.

## Projections of Dose from Food

- The recommended PAG is either 0.5 rem (5 mSv) committed effective dose equivalent, or 5 rem (50 mSv) committed dose equivalent to individual tissues and organs, whichever is more limiting.

**Notes:**
Using the formula given on this slide for the derived intervention level, the PAG can be converted to units of pCi per kilogram, and comparisons can be made with actual radionuclide concentrations in foods.  The PAG may be either 0.5 rem for committed effective dose equivalent, or 5 rem committed dose equivalent to individual tissues or organs, whichever is more limiting.

This calculation for the DIL incorporates the PAG value; the fraction, f, of food intake assumed to be contaminated; the quantity of food consumed in a specific time period, FI; and the dose coefficient, DC, that converts picocuries into mrem.

## Example of Projection of Dose from Food

- As the result of an NPP release, 90Sr has been released into a portion of the food supply.  What is the DIL for a population that may have to consume contaminated food for 100 days?

- If foodborne radionuclide concentrations exceed this value, the PAG is exceeded.

**Notes:**
As an example, a nuclear power plant release resulted in portions of the local food supply becoming contaminated with strontium-90.  If the food will be consumed by a population over the next 100 days, what strontium concentrations will not exceed the PAG for dose from food?

In this example, we assume the food supply to be half of the total food consumed by the population.  This is likely a very conservative estimate.  An individual will consume 300 kilograms of food over the 100-day period, and the dose coefficient, from the PAG Manual, is 3 E-4 millirem per picocurie.

Therefore, if the concentration of strontium in the food exceeds a derived intervention level of 2.6E4 picocuries per kilogram, the PAG would be exceeded.

## Drinking Water/Food PAGs

- Drinking water PAG is implemented using EPA’s derived response levels (DRLs)
- Food PAG is implemented using FDA’s derived intervention levels (DILs)
- DRLs and DILs may vary for the same radionuclide because of how they are derived
- For water intake (via other beverages or food intake), DILs and DRLs can be used together or independently

**Notes:**
As discussed earlier, the drinking water PAG uses derived response levels.  The FDA’s food PAG uses derived intervention levels.  The DRLs and DILs may vary for the same radionuclide because of differences in their derivation.  

The FDA Food PAG and the EPA Drinking Water PAGs are each derived assuming limited dose from the other pathway, so apply them independently.

Incident-specific calculations take into account real intakes, exposure paths and timeframes.  The default values in the PAG Manual tend to be conservative, especially the FDA DILs.  A user could decide to apply the water PAG separately allowing up to 0.5 rem projected dose from water and another 0.5 rem projected dose from food by disregarding the water contribution to a calculated Food DIL – the resulting total could approach 0.5 + 0.5 = 1 rem and this is consistent with the other Intermediate Phase PAGs.

## Conclusion

- Questions or comments on the food or drinking water PAG?

**Notes:**
Are there any questions or comments on the food or drinking water PAG?

## Break

**Notes:**
Another quick break before we hit the homestretch.  When we return in 10 minutes, we’ll talk about the Late Phase and optimization.

## Late Phase

- Cleanup and recovery
- Optimization
- Descriptions
- Optimization planning for radiological cleanup
- Resources for demonstrating completion
- Other recovery issues

**Notes:**
This information on the Late Phase PAGs, taken from the new revision of the manual, was not addressed in the 1992 version, so this is all brand new material when it comes to PAGs.

We now find ourselves in the Late Phase of a radiological incident.  This phase is characterized by site cleanup and recovery and may go on for years or even decades.  Earlier, in the workshop introduction, we briefly mentioned the concept of optimization.  We will spend some additional time on the details of this concept.

We will also identify available resources that can be used to demonstrate completion of the Late Phase activities, such as MARSSIM.  

Lastly, we’ll touch on several other recovery-related issues.

## Late Phase Goals

- Restoration of incident site to conditions as near as possible to pre-existing—creation of a “new normal”
- Remove contamination
- Eliminate access restrictions
- End food and water controls
- Return population to homes and jobs

**Notes:**
Ideally, the goal of the Late Phase is to restore the area affected by the radiological incident to as close to pre-incident conditions as possible.  This will require removal of contamination with residual contamination levels below agreed-upon cleanup criteria, if possible.  Once this has occurred, you can look at ending access restrictions, lifting food and water controls, and returning people to their homes and jobs.

## DHS Workgroup

- Addressed recovery and cleanup issues
- Determined that a numeric “cleanup level” was not useful (extreme range of impacts)
- Agreed to _optimization_ approach based loosely on the “Framework for Environmental Health Risk Management” (1997)
- DHS guidance was approved for interim use; EPA and DHS documents will be finalized in parallel

**Notes:**
The Department of Homeland Security took the lead in developing the Late Phase PAG.  A key finding of the RDD/IND Consequences Management Workgroup was the impracticality of designating a single numeric cleanup level.  In light of this finding, EPA is not proposing a numerical Late Phase PAG; instead, the agency recommends the use of an optimization method that allows for the benefits of the cleanup to be balanced against the possible negative consequences of the cleanup actions themselves.  In addition, different types of incidents may require different approaches to cleanup.  The optimization method allows for these variations in approach for the Late Phase.  The DHS Late Phase PAG document was issued for interim use; both the DHS guidance and the PAG Manual will be finalized in parallel – the comments you submitted on the DHS document have yet been addressed, but when they are, they will be incorporated in the EPA PAG Manual at the same time.

## Optimization Process

- Identify a variety of dose or risk benchmarks identified from state, federal, or other sources
- Use benchmarks as the basis for analyzing various options for remediation
- Establish cleanup goals based on the optimization analysis

**Notes:**
The optimization process is relatively straightforward.  It is a broadly defined concept that is common to many state, federal, and international risk management programs addressing radionuclides and hazardous chemicals.  It is a flexible approach in which a variety of dose or risk benchmarks may be identified from various regulatory agencies, state governments, or other stakeholders.  Federal benchmarks include those used by EPA, DOE, DOD, and NRC in accordance with a number of different statutes and their implementing regulations.  Other sources include the National Council on Radiation Protection and Measurements, the International Commission on Radiological Protection, and the International Atomic Energy Agency.  These benchmarks are useful for analysis of remediation options.  Establishment of cleanup goals in the optimization process are typically based on one or more of these benchmarks, along with the incorporation of other site-specific relevant factors.

## Optimizing for Recovery

- Optimization activities are quantitative and qualitative assessments applied during decision-making
- Optimized exposure levels for recovery may require consideration of net health benefits to the exposed population and society in general
- EPA recommends forming work groups to include:
- Various technical disciplines
- Members of the affected population
- Government agencies
- Public interest groups

**Notes:**
Optimization is a process used to determine society’s objectives for expected land uses, to develop and evaluate options and approaches, and to select the most acceptable recovery criteria.  Optimization activities can be both quantitative and qualitative assessments applied at each stage of the recovery decision-making process—from evaluation of remedial options to implementation of the chosen alternative.  EPA recommends forming work groups to focus exclusively on recovery and site restoration issues.  

Ideally, the optimized exposure level selected by the work group will be the level at which doses and risk from radiation exposure have been reduced as much as is possible given the circumstances, costs, and benefits, which may include financial and social considerations.

## Factors in the Optimization Process

- Nature of the incident—size, contaminants, location, special consideration items
- Technical feasibility—waste generation and disposal
- Adverse effects of the cleanup activities
- Effectiveness and permanence

- Areas impacted
- Types of contamination
- Other hazards present
- Human health
- Public welfare
- Ecological risks
- Actions already taken
- Projected land use
- Preservation or destruction of significant places
- Technical feasibility
- Wastes generated
- Disposal options
- Applicable resources
- Potential adverse impacts
- Long-term effectiveness
- Timeliness
- Public acceptability
- Economic effects

**Notes:**
The optimization analysis must consider a number of factors.  Among these are the nature of the incident, including such special considerations as historical, religious, and nationally significant items, the technical feasibility of each option, any adverse effects that might arise as a result of cleanup activities, and the effectiveness and permanence over the long term.  The box on the right side of the slide lists several considerations.

The draft PAG Manual provides a sample outline for an optimization plan.

The evaluation of options for the Late Phase after a radiological incident should take into account many of these factors—such as ecological risks, technical feasibility, and public acceptability.  However, in addition to the radiological component, a terrorist event may also require the consideration of biological and chemical contamination.

## Decision-Making Organizations

- Focus on process for reaching consensus: Identify stakeholders in the decision-making process
- Decision Team
- Senior federal and state officials
-  Recovery Management Team
- Senior leadership in the field recovery effort
- Stakeholder Working Group
- Federal, state, local business, local nongovernmental representatives, members of the public
- Technical Working Group
- Select subject matter experts

**Notes:**
It is very important that participants in the site restoration process be committed to the same outcome.  Consensus may be difficult to achieve, but it is essential to the success of the cleanup project.  A variety of working groups may be formed at various points in the process to guide and oversee activities.  Suggested work groups include a decision team, a recovery management team to oversee the field cleanup activities, a stakeholder working group, and a technical working group comprising relevant subject matter experts.  Ultimately, the nature of the incident will dictate the number and type of work groups formed.  However, in every case, it is critical that members of the affected population and other stakeholders be involved in the process.  

## Work Group Expertise Areas

- Health physics and radiation protection
- Environmental fate and transport sciences
- Decontamination technologies
- Radiation measurements

- Site-specific demographics, land uses, and local public works
- Local community needs, wants, and wishes
- Government
- Waste management

**Notes:**
Depending on the type of radiological incident, certain areas of expertise may be required.  This list represents the most likely areas, including health physicists, decontamination experts, public works experts, and members of federal, state, and local governments.

## Implementation of Site Restoration Plan

- Develop operational guidelines for specific activities
- Conduct cleanup activities per the plan
- Revisit and revise as conditions dictate

**Notes:**
Once the cleanup criteria have been agreed to, operational guidelines will be established.  These guidelines are derived values that can be measured with field or laboratory equipment, and they directly relate to the cleanup criteria. 

Cleanup activities should follow a plan but may have to be reconsidered or revised depending on site conditions. 

## Recovery Criteria Considerations

- Exposure pathways
- Direct external exposure (whole body dose)
- Ingestion
- Inhalation
- Affected populations include residents and workers
- Reasonable anticipated use of facility or area

**Notes:**
In developing recovery criteria, the various work groups will consider the exposure pathways, the affected populations, and the anticipated use of a contaminated facility or parcel of land.

## Existing Cleanup Benchmarks

- State environmental departments/programs
- Usually within risk range of 10-4 to 10-6
- NRC Agreement States
- 25 mrem/yr primary dose constraint (some states are more stringent—down to 10 mrem/yr)
- 100 mrem/yr allowable exemption
- ALARA
- NRC and DOE decommissioning programs
- 25 mrem/yr primary dose constraint
- 100 mrem/yr allowable exemption
- ALARA
- EPA Superfund sites
- risk range of 10-4 to 10-6

**Notes:**
These existing cleanup benchmarks, from a variety of state and federal government agencies, may be considered when determining specific cleanup criteria.  I am sure that some of these values are very familiar to some of you in the audience.

## Demonstrating Completion

- Several tools are available to assist in determining compliance with specified and agreed-upon cleanup criteria:
- Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)
- Methods for Evaluating the Attainment of Cleanup Standards (EPA 230/02-89-042)
- Soil Screening Guidance for Radionuclides:  Technical Background Document (EPA 540-R-00-007)
- Improving Sampling, Analysis, and Data Management for Site Investigation and Cleanup (EPA 542-F-04-001a)

**Notes:**
Several tools are available to help determine compliance with the selected cleanup criteria.  These include the Multi-Agency Radiation Survey and Site Investigation Manual and other EPA guidance documents such as those listed here that deal with sampling and analysis.

## Conclusion

- Questions or comments on the Late Phase PAG?

**Notes:**
We have _____ minutes of time to take some questions or comments on the Late Phase.  There are some other matters that we’ll be going over in just a bit.  

## 2007 PAG Manual Revision

- Not a substantial change from 1992
- Clarifies the use of PAGs for incidents other than nuclear power plant releases
- Provides drinking water guidance
- Introduces guidance for long-term site restoration
- Updates the dosimetry basis from ICRP 26 to ICRP 60

**Notes:**
As you can see, the revised PAG Manual that EPA is proposing does not substantially change the 1992 Manual, but instead it clarifies and expands the guidance.  It clarifies the use of PAGs for incidents other than nuclear power plant accidents, provides drinking water guidance, introduces guidance for long-term site restoration, and updates dosimetry from ICRP 26 to ICRP 60.  It also lowers the projected thyroid dose for implementing KI.  During this workshop, we have also walked through the different phases of an incident and discussed the application of the appropriate PAGs.

## Commenting on the Revised PAG Manual

- Availability of revised manual
- Public comment period
- Submission of comments
- Specific areas for requested comments

**Notes:**
Based on this information and your review of the manual once it is available on [DATE] via [MEANS], EPA would like your comments.  EPA will be publishing a notice in the Federal Register on or near [DATE] to request comments on the revised manual.  We welcome any and all comments you may have, but the next few slides (reproduced in your handouts) outline particular areas where we’d like to hear from you.  The comment period will last 60 days.  Please send your comments by email or regular mail to the addresses provided in the notice.  

## Note in the Revised PAG Manual

- New values for DCPs and DRLs are based on ICRP 60.
- EPA encourages the use of electronic tools, such as Turbo FRMAC.
- The drinking water PAG considers only ingestion; other uses (e.g., bathing, washing) are considered under the Intermediate Phase.
- The food PAG chapter is a copy of FDA guidance from 1998; comments on this topic may not be addressed until the next FDA revision

**Notes:**
When you are reviewing the revised manual, please note these points (included in your handouts).  

## Note in the Revised PAG Manual

- Late Phase guidance is based on a DHS document from 2006 and introduces optimization.
- Note that “relocation area” replaces “restricted zone” throughout the document.
- Additional language is provided to allow users to choose existing cleanup processes and levels or to employ the optimization process for incidents other than RDDs and INDs.
- DHS issued for interim use its document on applying PAGs to RDD and IND incidents in parallel and changes will be incorporated into the PAG Manual.

## Special Areas for Comment

- Can we further reduce the NPP-specific language to streamline the document?
- Should background information in Appendix C (from 1992) on sheltering be retained as part of the PAG basis?

**Notes:**
The following slides, which are included in your handouts, show the areas where EPA is particularly interested in your comments.  During the comment period, please address these areas along with any other concerns you may have.

## Special Areas for Comment

- Would a PAG for re-entry into a relocation area be helpful?
- Should the contamination guidance of 2 X background—for example, contamination rate for monitoring and decontamination at public reception centers—be retained?

## Special Areas for Comment

- Please comment on the usefulness of the drinking water PAG and supporting information.
- Please comment on the usefulness of the discussion in the revised manual on how the food and water PAGs work together.
- Should the food PAG be applied when an incident involves contaminated food and drinking water, and the drinking water PAG be applied to incidents involving only water contamination?

## Special Areas for Comment

- How is the new table of existing radiological cleanup benchmarks useful?
- Please comment on the removal of the “5 rem projected over 50 years” PAG, which was potentially confused with Late Phase/recovery guidance.

## Special Areas for Comment

- Appendices C, D, E, and F contain some old data related to the development of the PAGs; if made available online via the 1992 Manual, can they be cut from this version to streamline the document?
- Please comment specifically on the value of Appendices G and H, which support the Late Phase guidance.

## The End

- Thank you for your attention!

- Enjoy the rest of the day!

**Notes:**
We hope you have found this workshop to be informative and useful.  Please fill out the brief survey provided in your handouts.  This will help us to improve the workshop for future participants.

And, don’t forget to comment on the manual when it is released for comment!

Thank you, and enjoy the rest of your day.