**ACUTE LYMPHOBLASTIC LEUKEMIA**

**FALLON, NEVADA**

**REVIEW AND RECOMMENDATIONS**

**OF THE**

**EXPERT PANEL**

**February 15, 2001**

Members:

Leslie L. Robison, PhD

Professor, Department of Pediatrics, School of Medicine

Director, Division of Pediatric Epidemiology and Clinical Research

University of Minnesota Cancer Center

Thomas Sinks, PhD

Associate Director for Science

National Center for Environmental Health

Centers for Disease Control and Prevention

Allan H. Smith, MD, PhD

Professor of Epidemiology, School of Public Health

University of California, Berkeley

Malcolm Smith, MD, PhD

Head, Pediatric Section, Cancer Therapy Evaluation Program

National Cancer Institute, National Institutes of Health

The expert panel was convened on February 15, 2001, in Reno, Nevada by
Dr. Mary Guinan, Nevada State Health Officer. The panel reviewed the
state health department's investigation of acute lymphoblastic leukemia
(ALL) cases that had been diagnosed in Churchill County, Nevada. The
panel considered possible follow-up actions and priorities by the Nevada
Health Division. The meeting of the expert panel was attended by panel
members and staff from the Nevada Health Division, University of Nevada
School of Medicine, Nevada Governor's Office, U.S. Senate (Senator John
Ensign's Office and Senator Reid's staff on U.S. Senate Committee on
Environment and Natural Resources), and the Fallon Naval Air Base. This
report summarizes the panel's review and recommendations.

The expert panel recognized the difficulty in evaluating and
investigating excess occurrences of ALL. The panel members acknowledged
that the cause(s) of ALL are insufficiently understood to single out a
specific factor as explaining the observed excess in Fallon, Nevada. The
panel members were familiar with previous investigations of ALL
clusters, all of which had failed to uncover an explanation of the cause
of these excesses. At the same time, the panel members confirmed that
the excess occurrence of ALL in Fallon, Nevada is unusual; not only
because of its large number of observed cases among so small a
population-at-risk over a short time period, but also because further
observed ALL cases had been diagnosed after the initial recognition of
the ALL excess. The members of the expert panel acknowledged the
excellent work of the staff of the Nevada Health Division on this
investigation.

Scientific understanding of the biology of ALL prevented the committee
members from predicting the cause of the observed epidemic. The
committee is aware of at least three distinct sets of possibilities. The
first set of theories collectively point toward a cancer causing
chemical contaminant (e.g., human carcinogen) as the causal agent for
the ALL epidemic. Theories about a chemical in the environment have
received the greatest amount of public attention and community concern.
The expert panel recognizes the need to address community concern
regarding the presence of a hazardous chemical contaminant. However, the
absence of cases of acute myeloid leukemia, the type of leukemia most
commonly associated with toxic chemical exposure ([1-3](#reference_1)),
argues against the Fallon cases being the result of toxic exposures. The
panel members were skeptical that a chemical exposure could explain the
ALL epidemic in Fallon, Nevada.

A second possible explanation relates to the theory of what is called
***population mixing**,* in which clusters of ALL have been reported
associated with unusual mixing of people, often in relatively isolated
rural areas ([4-11](#reference_4)). The population mixing theory
initially focused on the possibility of an unidentified infectious agent
(i.e., a virus). However, the current consensus is that exposure to a
variety of infectious agents (i.e., viral and bacterial) may trigger an
unusual and rare reaction that affects a very small number of children
within the susceptible population. The hypothesis suggests that ALL is
not infectious, spreading from one person to another; but an unusual
complication to a common infection within a susceptible population. The
population-mixing theory is supported by the observation that excesses
of ALL eventually subside, presumably because of increased population
immunity. This theory requires further examination. The panel believes
it reasonable to test this hypothesis by calculating rates of ALL in
other rural areas of the U.S. having significant population mixing.
However, such an effort falls outside the mandate of the Nevada Health
Division. Finally, the possibility that the epidemic of ALL cases is due
to random chance cannot be totally excluded as an explanation. The panel
acknowledges, however, that the ALL epidemic in Fallon, Nevada is not
likely to represent a "chance" occurrence.

The expert panel recommends to the Nevada Health Division six follow-up
steps in the investigation of the excess occurrence of ALL in Fallon,
Nevada (see [Table 1](#Table_1)). The purpose of these next steps are to

1)  efficiently expand case-finding efforts,

2)  categorize the observed ALL cases by clinically relevant disease
    biomarkers,

3)  identify potential excess environmental exposures unique to the
    community by a cross-sectional exposure assessment of **selective**
    contaminants and an evaluation of contaminant releases into the
    local environment with assessment of completed pathways for the case
    families,

4)  collect and bank biologic specimens for future scientific
    investigations,

5)  determine the time course and characteristics of population
    movements into the Fallon area for the period 1990 to 2000, and

6)  maintain an expert panel to peer review investigative protocols and
    study results, consider future use of banked specimens, and provide
    ongoing consultation to the Nevada Health Division.

The expert panel also discussed the importance of high concentrations of
arsenic in municipal and private drinking water supplies. The panel
members expressed doubt that arsenic consumption in drinking water, by
itself, could explain the observed ALL excess for several reasons:

1)  The excess occurrence of ALL began in 1999, whereas the arsenic
    concentrations in drinking water have been consistently elevated for
    many years.

2)  The case children who make up the excess occurrence of ALL differ in
    respect to their consumption of arsenic-contaminated drinking water.

3)  Epidemiologic studies of arsenic-exposed populations have not linked
    arsenic exposure with adult or childhood leukemia.

One recent article suggests a weak association between childhood
leukemia risk and exposure to low levels of arsenic in drinking water
([12](#reference_12)). The panel has reviewed the article and believes
that the study is inadequate to support a conclusion that ALL is related
to arsenic in drinking water. Each panel member expressed concern that
the ongoing exposure to excess levels of arsenic in drinking water was a
human health hazard, regardless of its relationship to the excess of
ALL. The Fallon municipal water supply is contaminated with arsenic (As)
at a level 10 times the EPA recommended standard for arsenic in drinking
water. The panel was also aware that an unknown proportion of Churchill
County drinking water wells, unregulated by the federal Safe Drinking
Water Act (SDWA), are at least as contaminated as the Fallon municipal
water supply. Arsenic is recognized by the Report on Carcinogens of the
National Toxicology Program as a known human carcinogen on the basis of
epidemiologic studies that have linked arsenic exposure with an excess
of skin, bladder, and lung cancers in exposed human populations.

The expert panel recommends that arsenic concentrations in the Fallon
municipal drinking water be reduced to a level no more than that
currently recommended by EPA (e.g., 10 µg/L) as soon as possible. The
panel strongly encourages the Nevada Health Division, and other state
agencies, to proceed with recommendations for testing arsenic in all
drinking-water wells in Churchill County that are unregulated by the
SDWA. The state health division should work to create a process
providing this service when necessary and develop a set of
recommendations for preventing arsenic exposure based on reported test
results. The state health division should consider maintaining a listing
of wells that have been tested, along with test results.

+-------+--------------------------------+-----------+----------------+
| [     |                                |           |                |
| ]{#Ta |                                |           |                |
| ble_1 |                                |           |                |
| .anch |                                |           |                |
| or}** |                                |           |                |
| Table |                                |           |                |
| 1:    |                                |           |                |
| Inv   |                                |           |                |
| estig |                                |           |                |
| ating |                                |           |                |
| the   |                                |           |                |
| e     |                                |           |                |
| xcess |                                |           |                |
| occur |                                |           |                |
| rence |                                |           |                |
| of    |                                |           |                |
| Acute |                                |           |                |
| Lym   |                                |           |                |
| phobl |                                |           |                |
| astic |                                |           |                |
| Leu   |                                |           |                |
| kemia |                                |           |                |
| in    |                                |           |                |
| Fa    |                                |           |                |
| llon, |                                |           |                |
| Ne    |                                |           |                |
| vada; |                                |           |                |
| Phase |                                |           |                |
| II    |                                |           |                |
| Recom |                                |           |                |
| menda |                                |           |                |
| tions |                                |           |                |
| of    |                                |           |                |
| the   |                                |           |                |
| E     |                                |           |                |
| xpert |                                |           |                |
| Panel |                                |           |                |
| (Feb  |                                |           |                |
| ruary |                                |           |                |
| 15,   |                                |           |                |
| 20    |                                |           |                |
| 01)** |                                |           |                |
+=======+================================+===========+================+
| **    | **TASK**                       | **TIME    | **C            |
| PRIOR |                                | FRAME**   | OLLABORATORS** |
| ITY** |                                |           |                |
+-------+--------------------------------+-----------+----------------+
| 1     | Efficiently expand             | These     | Clinical       |
|       | case-finding efforts. The      | a         | Oncology       |
|       | panel members encourage the    | dditional | Group,         |
|       | Nevada Health Division to      | steps     | California     |
|       | continue limited case-finding  | could be  | Tumor          |
|       | strategies. The panel members  | done      | Registry,      |
|       | recommended limited expansion  | within 2  | California ALL |
|       | of case-finding by linking to: | months    | research team. |
|       |                                | after     |                |
|       | A.  The national Childhood     | sat       |                |
|       |     Oncology Group (COG)       | isfactory |                |
|       |     databases(s) to identify   | neg       |                |
|       |     all children with ALL      | otiations |                |
|       |     having a residence at time | regarding |                |
|       |     of diagnosis in the state  | patient   |                |
|       |     of Nevada. The purpose of  | confid    |                |
|       |     this would be to evaluate  | entiality |                |
|       |     completeness of the Nevada | are       |                |
|       |     tumor registry and         | c         |                |
|       |     identify additional ALL    | ompleted. |                |
|       |     cases from Churchill       |           |                |
|       |     County.                    |           |                |
|       |                                |           |                |
|       | B.  An ongoing case-control    |           |                |
|       |     study of ALL being         |           |                |
|       |     conducted in California to |           |                |
|       |     review residential history |           |                |
|       |     of cases for previous      |           |                |
|       |     residence in Churchill     |           |                |
|       |     County, Nevada.            |           |                |
|       |                                |           |                |
|       | C.  The California State Tumor |           |                |
|       |     Registry to identify any   |           |                |
|       |     children with ALL with a   |           |                |
|       |     Nevada residence at time   |           |                |
|       |     of diagnosis.              |           |                |
+-------+--------------------------------+-----------+----------------+
| 2     | Categorize the observed ALL    | The       | Pediatric      |
|       | cases by clinically relevant   | health    | oncologists,   |
|       | disease biomarkers. Cancer     | division  | Childhood      |
|       | cells from each case-child     | should    | Oncology       |
|       | have probably been collected   | proceed   | Group,         |
|       | and undergone                  | to        | National       |
|       | immunophenotyping and          | determine | Cancer         |
|       | cytogenetic testing. The       | ava       | Institute.     |
|       | health division should collect | ilability |                |
|       | this information. If testing   | of data   |                |
|       | has not been done and tumor    | or tumor  |                |
|       | cells have been stored, the    | cells as  |                |
|       | health division should secure  | soon as   |                |
|       | samples and have them tested.  | possible. |                |
|       | These materials could be       |           |                |
|       | reviewed or tested at two      |           |                |
|       | independent laboratories. The  |           |                |
|       | distribution of these results  |           |                |
|       | among the case-children from   |           |                |
|       | Fallon can be compared against |           |                |
|       | other children with ALL to     |           |                |
|       | determine if these             |           |                |
|       | distributions are similar or   |           |                |
|       | if the distribution among the  |           |                |
|       | Fallon case-series is unique.  |           |                |
+-------+--------------------------------+-----------+----------------+
| 3     | Identify potential excess      | These     | National       |
|       | environmental exposures unique | a         | Center for     |
|       | to the community. The health   | ctivities | Environmental  |
|       | division should conduct        | will      | Health,        |
|       | limited testing for            | require   | Centers for    |
|       | [current]{.underline}          | de        | Disease        |
|       | exposures in environmental     | velopment | Control and    |
|       | media or human samples as well | of survey | Prevention;    |
|       | as evaluate contaminant        | and       | Agency for     |
|       | releases into the local        | sampling  | Toxic          |
|       | environment and assess the     | protocols | Substances and |
|       | potential for human exposure   | and       | Disease        |
|       | to such contaminants. This     | ap        | Registries;    |
|       | analysis would be used to      | propriate | Jonathan       |
|       | identify chemicals that are    | review of | Buckley for    |
|       | (and are not) elevated in the  | consent   | input on       |
|       | community and to consider if   | forms and | measuring      |
|       | additional data collection is  | confid    | housedust for  |
|       | required.                      | entiality | pesticide      |
|       |                                | ag        | residues,      |
|       | A.  A cross-sectional exposure | reements. | heavy metals,  |
|       |     assessment of selective    | The       | PAHs.          |
|       |     contaminants would include | committee |                |
|       |     examination of drinking    | an        |                |
|       |     water, human blood and     | ticipates |                |
|       |     urine of family members,   | startup   |                |
|       |     and possibly dust          | of these  |                |
|       |     collected from homes where | a         |                |
|       |     case-children did and did  | ctivities |                |
|       |     not live. Testing should   | during    |                |
|       |     be limited to compounds    | the       |                |
|       |     for which normative data   | months of |                |
|       |     are available. The expert  | March or  |                |
|       |     panel recommended testing  | April and |                |
|       |     for volatile organic       | available |                |
|       |     compounds in drinking      | results   |                |
|       |     water and human tissues;   | within 1  |                |
|       |     radioactive isotopes in    | year.     |                |
|       |     drinking water; selected   |           |                |
|       |     heavy metals in drinking   |           |                |
|       |     water, household dust, and |           |                |
|       |     human tissues; and         |           |                |
|       |     pesticides in human        |           |                |
|       |     tissues and in household   |           |                |
|       |     dust.                      |           |                |
|       |                                |           |                |
|       | B.  An evaluation of           |           |                |
|       |     contaminant releases into  |           |                |
|       |     the local environment with |           |                |
|       |     assessment of completed    |           |                |
|       |     pathways for the case      |           |                |
|       |     families. The expert panel |           |                |
|       |     recommends collecting      |           |                |
|       |     environmental release      |           |                |
|       |     data, including that from  |           |                |
|       |     local industry and the     |           |                |
|       |     Fallon Naval Airbase. An   |           |                |
|       |     assessment of the          |           |                |
|       |     potential for              |           |                |
|       |     environmentally released   |           |                |
|       |     chemicals to result in     |           |                |
|       |     human exposure should also |           |                |
|       |     be conducted, including    |           |                |
|       |     potential for              |           |                |
|       |     case-children to have been |           |                |
|       |     exposed.                   |           |                |
+-------+--------------------------------+-----------+----------------+
| 4     | Collect and bank biologic      | Specimen  | Nevada Public  |
|       | specimens for future           | c         | Health         |
|       | scientific investigations. The | ollection | Laboratory,    |
|       | members of the panel recognize | could     | National       |
|       | how limited our knowledge is   | occur     | Center for     |
|       | of the cause(s) of ALL and the | simul     | Environmental  |
|       | difficulty investigators have  | taneously | Health,        |
|       | had in identifying the causes  | with the  | Centers for    |
|       | of similar ALL excesses. The   | exposure  | Disease        |
|       | panel members believe that     | a         | Control and    |
|       | collection of biologic         | ssessment | Prevention,    |
|       | specimens from case-children   | (see 3A)  | National       |
|       | and family members may be      | or        | Cancer         |
|       | useful for future research     | include   | Institute as   |
|       | investigations into the        | samples   | possible       |
|       | cause(s) of ALL. A small       | taken     | repositories   |
|       | amount of blood and urine, and | during    | for the tissue |
|       | perhaps buccal cells, should   | clinical  | bank.          |
|       | be collected, maintained, and  | care. A   |                |
|       | made available for future      | protocol  |                |
|       | research.                      | for       |                |
|       |                                | co        |                |
|       |                                | llection, |                |
|       |                                | storage,  |                |
|       |                                | and       |                |
|       |                                | access to |                |
|       |                                | samples   |                |
|       |                                | must be   |                |
|       |                                | developed |                |
|       |                                | and       |                |
|       |                                | reviewed  |                |
|       |                                | by an     |                |
|       |                                | Inst      |                |
|       |                                | itutional |                |
|       |                                | Review    |                |
|       |                                | Board for |                |
|       |                                | c         |                |
|       |                                | ompliance |                |
|       |                                | with      |                |
|       |                                | human     |                |
|       |                                | subject   |                |
|       |                                | research. |                |
+-------+--------------------------------+-----------+----------------+
| 5     | Determine the time course and  | Initial   | Public school  |
|       | characteristics of population  | data      | systems and    |
|       | movement into the Fallon area  | c         | Fallon Naval   |
|       | for the period 1990-2000. The  | ollection | Airbase (for   |
|       | expert panel recommends        | within 2  | information    |
|       | collecting demographic data    | months.   | concerning     |
|       | concerning changes in the      |           | migration      |
|       | population of Fallon,          |           | patterns),     |
|       | specifically looking for       |           | Drs. Les       |
|       | evidence of large migration of |           | Robison and    |
|       | new long-term residents into   |           | Malcolm Smith  |
|       | the community during this time |           | (for           |
|       | period. The appended table     |           | consultation   |
|       | illustrates the kind of        |           | to identify    |
|       | first-level information that   |           | the specific   |
|       | is relevant to this issue.     |           | data           |
|       |                                |           | required).     |
+-------+--------------------------------+-----------+----------------+
| 6     | Maintain the expert panel to   |           |                |
|       | peer review investigative      |           |                |
|       | protocols and study results,   |           |                |
|       | review proposals for future    |           |                |
|       | use of banked specimens, and   |           |                |
|       | provide ongoing consultation   |           |                |
|       | to the Nevada Health Division. |           |                |
+-------+--------------------------------+-----------+----------------+

#  **Reference List**

[]{#reference_1 .anchor}1. Felix CA. Secondary leukemias induced by
topoisomerase-targeted drugs. Biochim Biophys Acta 1998;233-55.

2\. Bennett JM, Moloney WC, Greene MH, Boice JD. Acute myeloid leukemia
and other myelopathic disorders following treatment with alkylating
agents. Hematol Pathol 1987;99-104.

3\. Rothman N, Smith MT, Hayes RB, Traver RD, Hoener B, Campleman S, Li
GL, Dosemeci M, Linet M, Zhang L, Xi L, Wacholder S, Lu W, Meyer KB,
Titenko-Holland N, Stewart JT, Yin S, Ross D. Benzene poisoning, a risk
factor for hematological malignancy, is associated with the NQO1
609C\--\>T mutation and rapid fractional excretion of chlorzoxazone.
Cancer Res 1997;2839-42.

[]{#reference_4 .anchor}4. Kinlen LJ. Epidemiological evidence for an
infective basis in childhood leukaemia \[editorial\]. Br J Cancer
1995;1-5.

5\. Kinlen LJ, Clarke K, Hudson C. Evidence from population mixing in
British New Towns 1946-85 of an infective basis for childhood leukaemia.
Lancet 1990;577-82.

6\. Kinlen LJ, Hudson C. Childhood leukaemia and poliomyelitis in
relation to military encampments in England and Wales in the period of
national military service, 1950-63. BMJ 1991;1357-62.

7\. Kinlen LJ, O\'Brien F, Clarke K, Balkwill A, Matthews F. Rural
population mixing and childhood leukaemia: effects of the North Sea oil
industry in Scotland, including the area near Dounreay nuclear site. BMJ
1993;743-8.

8\. Kinlen LJ, Petridou E. Childhood leukemia and rural population
movements: Greece, Italy, and other countries. Cancer Causes Control
1995;445-50.

9.  Kinlen LJ. High-contact paternal occupations, infection and
    childhood leukemia: five studies of unusual population-mixing of
    adults. Br J Cancer 1997;1539-1545.

10\. Alexander FE, Chan LC, Lam TH, Yuen P, Leung NK, Ha SY, Yuen HL, Li
CK, Li CK, Lau YL, Greaves MF. Clustering of childhood leukaemia in Hong
Kong: association with the childhood peak and common acute lymphoblastic
leukaemia and with population mixing. Br J Cancer 1997;457-63.

11\. Petridou E, Revinthi K, Alexander FE, Haidas S, Koliouskas D,
Kosmidis H, Piperopoulou F, Tzortzatou F, Trichopoulos D. Space-time
clustering of childhood leukaemia in Greece: evidence supporting a viral
aetiology. Br J Cancer 1996;1278-83.

[]{#reference_12 .anchor} 12. Infante-Rivard et al. Drinking water
contaminants and childhood leukemia. Epidemiology 2001;12:13-19.

Appendix I: Recommended\* Data to Evaluate Population Dynamics in
Fallon, NV

<table style="width:100%;">
<colgroup>
<col style="width: 30%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
<col style="width: 6%" />
</colgroup>
<tbody>
<tr class="odd">
<td><p>Estimated Populations</p>
<p>within Groups</p></td>
<td>1990</td>
<td>1991</td>
<td>1992</td>
<td>1993</td>
<td>1994</td>
<td>1995</td>
<td>1996</td>
<td>1997</td>
<td>1998</td>
<td>1999</td>
<td>2000</td>
</tr>
<tr class="even">
<td><strong>Fallon</strong> Total</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td>Individuals &lt;21 yrs</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Individuals &lt;10 yrs</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td><strong>Military Base</strong> Total personnel</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Permanent (&gt;6 mos)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td>Temporary (<u>&lt;</u> 6 mos)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Dependents (total)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td>Dependents &lt;20 yrs of age</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td><strong>School Enrollment</strong> K-12 (Total)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td>Elementary (Total)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Middle School (Total)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td>High School (Total)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Total K-12 (Naval dependents)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td><p>Elementary</p>
<p>(Naval dependents)</p></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="even">
<td>Middle School (Naval dependents)</td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
<tr class="odd">
<td><p>High School</p>
<p>(Naval dependents)</p></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
<td></td>
</tr>
</tbody>
</table>

\*It is recognized that the figures requested may not be available for
all categories and/or years. Although the objective would be to obtain
the most detailed and accurate information possible, crude estimates
would be preferable to no information. Accordingly, it will be important
to document the level of confidence (i.e., accuracy) for the various
pieces of information obtained.