Review of the Incidence of Cancer Cases among Residents of Rowan 

County, North Carolina, and Residents Living Near Industrial 

Facilities in Salisbury, North Carolina 

February 2006 

“This information is distributed by the Agency for Toxic Substances and Disease Registry for public 

comment under applicable information quality guidelines. It does not represent and should not be 

construed to represent final agency conclusions or recommendations.” 

U.S. Department of Health and Human Services 

Agency for Toxic Substances and Disease Registry 

Division of Health Studies 

Atlanta, Georgia 30333
Summary

To address community concerns about an increased occurrence of cancer, we compared cancer 

rates among people living within 1 mile of industrial facilities on Jake Alexander Boulevard in 

Salisbury, North Carolina, with cancer rates among people living in Rowan County for the years 

1990–2000. We found the standardized incidence rates for oral cancers and all cancers in the 

Salisbury area were lower than the Rowan County rates. Because of a request from a former 

resident of this neighborhood, we also analyzed cancer rates among residents of two specific 

census block groups—0513031 and 0513032—near the industrial site. When calculated for total 

cancer, for lymphoma, and for brain cancer, we found the cancer rates in the two census blocks 

were statistically significantly higher than the rates for residents living within the 1 mile area. 

But this finding is based on only seven lymphoma cases and six brain cancer cases, and any 

additional interpretative data (e.g., personal or occupational cancer risks) are unavailable. Thus at 

this time ATSDR cannot establish any casual relationship between these elevated rates and any 

contaminant or condition in the test area. 

Background

A former resident of Milford Hills, a neighborhood near the industrial facilities, noticed that 

many area residents had cancer. This resident was concerned that the air and water pollution 

from a nearby industrial area on Jake Alexander Boulevard might be causing these cancers. The 

area in question contains a gas fuel processing and shipping plant and an asphalt production and 

shipping plant. Nearby residents complained of odors and polluted groundwater, and expressed 

concern that this pollution was causing their illnesses. To respond to this concern, staff from the 

North Carolina Central Cancer Registry examined the occurrence of selected cancers in that area. 

In a report entitled “Evaluation of Reported Cluster of Cancer Cases Salisbury, North Carolina,” 

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Dale Herman found that the age-adjusted incidence rates for 26 different types of cancers 

observed among residents of Rowan County were either lower than or equal to expected 

incidence rates. The report explained that the age-adjusted rate for brain cancer within 1 mile of

the asphalt plant located on Jake Alexander Boulevard was 1.89 times as many as would be 

expected when compared with people living in other counties in North Carolina (North Carolina 

Department of Health and Human Services 2003). Following the release of this report, the 

petitioner requested further review of the cancer data by the Agency for Toxic Substances and 

Disease Registry (ATSDR). 

Because information describing the specific chemicals and levels of exposure from industrial 

pollutants was not available, we defined “exposure” as the area within 1 mile of the industrial 

facilities. We then determined the number of people with the same types of cancer as reported by 

the North Carolina Central Cancer Registry who lived within 1 mile of the Jake Alexander 

Boulevard industrial facilities. The census block groups that were examined were 0513031, 

0513032, 0513033, 0513034, 505003, 504002, and 0512021. These blocks included all of the 

neighborhoods within 1 mile surrounding the industrial facilities (Figure 1 & 2). 

We estimated the expected number of cases within 1 mile of the facilities by multiplying the 

Rowan County cancer-specific rates by the estimated number of people living within the 

prescribed 1 mile area. We estimated the number of people living in that area by applying the 

proportion of the census block group included within 1 mile area of the plants to the average 

number of people living in the total area of the census blocks as reported by the Bureau of the 

Census in 1990 and 2000. We then compared the expected number of cancers to the number of 

cancer cases reported to the cancer registry and obtained an estimate known as a standardized 

incidence ratio (SIR). 

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We then adjusted this and other ratios for age. The ratios for certain gender-specific cancers, 

such as breast cancer, were adjusted for both age and sex. Adjusting is a way to control for 

differences in age and sex distribution among populations in two areas, given that cancers occur 

at different rates as men and women age. When the number of cases of a certain type of cancer 

was fewer than six in any of the analyzed census blocks, the actual number of cases was not 

reported, thus reducing the possibility that any persons might be identified. 

In addition to the Bureau of the Census data, we also reviewed tax parcel data to verify the 

appropriateness of using the 1 mile boundary as a measure of exposure and to ensure the study 

population included a majority of residents who were most likely to be exposed. Block groups 

0513031 and 0513032, which can be described as the Milford Hills neighborhood, accounted for 

65% of the total number of homes within the 1 mile radius (Table 1). In the census block group 

0513031, 100% of the homes contributed to the 1 mile radius. Similarly, 84% of the homes in 

census block group 0513032 contributed to the study population within the 1 mile area (Table 2). 

Results

From 1990 to 2000, among residents living within 1 mile of the industrial facilities, 105 persons 

developed cancer (Table 3), with lung, breast, prostate, and colon cancers as the most common. 

This ranking was similar to the cancers diagnosed in the state of North Carolina and in the 

United States as a whole. 

No cancers were found to be statistically significantly elevated among residents living within the 

1 mile radius. Oral cancer and total cancer had, however, statistically lower rates. 

Despite the small number of cancer cases and the small number of residents, in response to 

community concerns we also analyzed the rates in two other census block groups: 0513031 and 

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0513032. The standardized incidence rates indicated that within these two block groups, 

lymphomas were diagnosed almost five times more often than would be expected in Rowan 

County residents. Also, brain cancers were diagnosed six times more often than they were in 

Rowan County (Table 4). That said, however, these results were based on estimates using very 

few cases (i.e., six brain cancer cases and seven lymphoma cases). While the estimates for the 

occurrence of many other types of cancer in these two census blocks were elevated, none of their 

rates were found to be statistically significant. 

Conclusion

The results of this cancer data review suggest that persons living within 1 mile of the industrial 

plants near Jake Alexander Boulevard during 1990–2000 did not have a statistically significant 

higher rate of cancer than 1) other residents of Rowan County, 2) other residents in the state of 

North Carolina, or 3) people throughout the United States. The residents of census block groups 

0513031 and 0513032, however, did have a statistically significant higher rate of lymphoma and 

brain cancer than did those who live in Rowan County. For the other types of cancers, the rates 

among the residents of the two census block groups did not differ statistically from the rates in 

Rowan County as a whole. 

Because data on individual risk factors for developing cancer (e.g., smoking, nutrition, family 

history), work-related exposures to cancer-causing chemicals, and residency were not available, 

this analysis cannot explain why the rates of certain cancers among residents of the two block 

groups appear elevated. Information about the quantities and types of chemicals to which people 

may have been exposed is unknown as well. Nevertheless, these are all known cancer risk 

factors, and they could explain the difference in the expected and in the actual number of cancers 

diagnosed among residents within 1 mile of the Salisbury industrial site. 

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Additionally, persons reported as living in the study area at the time of the cancer diagnosis may 

have only recently moved to the neighborhood. It is also possible that persons who once lived in 

the study area may have moved away before they learned of their cancer diagnosis. 

With regard to the findings of lymphoma and brain cancer in the two census blocks, the limited 

overall number of cases and the lack of information about possible risk factors and chemical 

exposures weaken any observed statistically significant increase. While the number of lymphoma

and brain cancer diagnoses among residents of blocks groups 0513031 and 0513032 from 1990–

2000 may have been greater than expected, the results cannot explain how or why these rates 

may have been elevated. Additionally, the results cannot be generalized to other populations who 

live near other asphalt or petroleum production and transport facilities. 

The cancers diagnosed among the residents living within 1 mile of the industrial facility on Jake 

Alexander Boulevard may have been related to exposures from the industrial facilities, exposures 

at the workplace, and exposures at a previous residence. Or they may have been associated with 

other, unmeasured risk factors such as smoking, diet, or a family history of disease. A review of 

cancer registry data is not designed to determine whether exposure to the industrial pollutants 

may have caused these cancers. 

ATSDR believes, however, that the data from the North Carolina Central Cancer Registry is 

complete. As with any registry data, the potential for some missed cases is always present. Still, 

according to the North American Association of Central Cancer Registries—a professional group 

that develops and promotes uniform data standards for cancer registration—this registry collects 

between 90–95% of all diagnosed cancers. 

(http://www.naaccr.org/index.asp?Col_SectionKey=12&Col_ContentID=54 ). 

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Recommendations

ATSDR scientists will continue to collect data to describe the different chemicals that may be in 

the area. The North Carolina Central Cancer Registry also plans continued monitoring of the 

rates at which new Rowan County cancer cases occur. 

Authors 

Stephanie Foster, MPH, MA 

Alden Henderson, PhD, MPH 

Acknowledgements 

The authors thank Gustavo Fernandez, Karen Knight, and Dianne Enright of the North Carolina 

Central Cancer Registry for their assistance in providing cancer data and to Randall Young of 

ATSDR/GRASP for his mapping expertise. 

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Figure 1. Site area map 

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Figure 2. Map of Salisbury, North Carolina, showing residential housing units by census 

block group 

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Table 1. Number and Cumulative Percentage of Housing units by Block Group Contained 

Within the 1-Mile Study Area (Rowan County Tax Parcel Data 2004) 

Housing unit by Block 

Group 

Estimated number of 

housing units in analysis 

Block Group 

Percentage of housing units 

of Block Group in 1 mile 

0504002 0 0% 

0505003 16 2% 

0512021 55 6% 

0513031 300 32% 

0513032 306 33% 

0513033 77 8% 

0513034 176 19% 

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Table 2. Number and percentage of housing units from Rowan County Tax parcel data by 

census block group 

Housing unit by 

Block Group 

Number of housing 

units in Census 

Block Group 

Estimated number 

of housing units in 

analysis Block 

Group 

Percentage of 

housing units in 

analysis Block 

Group (%) 

0513031

single unit 300 300 100 

multiple units 0 0 0 

total units 300 300 100% 

0513032 

single unit 365 306 84% 

multiple units 0 0 0 

total units 365 306 84% 

0513034

single unit 106 73 69% 

multiple units 70 45 64% 

total units 176 118 67% 

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Table 3. The Number and Percentage of Select Cancers by Primary Tumor Site and 

Location, 1990–2000 

Primary Cancer Site 

Number of cases in 

Rowan County 

N (%) 

Number of cases 

within 1mile of asphalt 

plant 

N (%) 

Bladder 237 (5.0) 6 (5.7) 

Brain 100 (2.1) 6 (5.7) 

Breast (Female) 724 (15.3) 23 (21.9) 

Cervix 83 (1.7) ≤5* 

Colon 440 (9.3) 8 (7.6) 

Corpus Uteri 129 (2.7) ≤5* 

Esophagus 33 (0.7) ≤5* 

Hematopoietic 176 (3.7) ≤5* 

Hodgkin’s Disease 22 (0.5) ≤5* 

Kidney 113 (2.4) 0 

Leukemia 124 (2.6) ≤5* 

Lung 727 (15.4) 12 (11.4) 

Lymphoma 175 (3.7) 7 (6.7) 

Multiple Myeloma 39 (0.8) ≤5* 

Non-Hodgkin’s Lymphoma 7 (0.2) 0 

Oral 91 (1.9) ≤5* 

Ovary 96 (2.0) ≤5* 

Pancreas 93 (2.1) ≤5* 

Prostate 487 (10.3) 8 (7.6) 

Stomach 72 (1.5) ≤5* 

All Cancers 4720 105 

* When the number of cancer cases of a certain type of cancer was less than six in any of the areas that were

analyzed, the actual number of cases is not reported to reduce the possibility that individuals will be identified.

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Table 4. Age-Adjusted Standardized Cancer Incidence Rates in the One-Mile Area 

Surrounding Industrial Facilities on Jake Alexander Boulevard, Salisbury, North Carolina 

and in Two Specific Census Block Groups, 1990-2000 

Site 

SIR 

within 

1 mile 

of 

asphalt 

plant 

95%

confidence 

interval 

SIR 

Block 

Groups 

0513031 

& 

0513032 

95%

confidence interval 

Bladder 0.81 (0.30, 1.77) 2.32 (0.75, 5.42) 

Brain 1.70 (0.45, 4.33) 6.16 (1.66, 15.78)*

Breast (Female) † 1.13 (0.72, 1.70) 1.39 (0.82, 2.20) 

Cervix 0.45 (0.01, 2.49) 0 -- 

Colon 0.57 (0.25, 1.13) 3.71 (0.76, 3.89) 

Corpus Uteri † 0.84 (0.17, 2.46) 1.31 (0.26, 3.82) 

Esophagus 2.11 (0.24, 7.62) 3.30 (0.04, 18.38) 

Hematopoietic 1.03 (0.33, 2.41) 2.20 (0.44, 6.43) 

Hodgkin’s Disease 1.68 (0.02, 9.33) 0 -- 

Kidney 0 -- 0 -- 

Leukemia 0.89 (0.18, 2.60) 2.22 (0.25, 8.01) 

Lung 0.57 (0.30, 1.00) 1.40 (0.64, 2.66) 

Lymphoma 1.37 (0.55, 2.83) 4.94 (1.80, 10.76)*

Multiple Myeloma 0.85 (0.01, 4.70) 0 -- 

Non-Hodgkin’s 

Lymphoma 0 -- 0 -- 

Oral 0.12 (0.02, 0.36)* 1.40 (0.02, 7.76) 

Ovary † 0.81 (0.09, 2.93) 0.64 (0.01, 3.56) 

Pancreas 1.08 (0.22, 3.16) 2.35 (0.26, 8.50) 

Prostate † 0.54 (0.23, 1.06) 0.98 (0.42, 1.94) 

Stomach 0.44 (0.01, 2.47) 0.44 (0.01, 2.47) 

All Cancers 0.77 (0.62, 0.93)* 1.32 (1.07, 1.60)* 

* Statistically significant results 

† Sex-specific rates 

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What We Have Learned About Cancer in our Neighborhood 

What do I need to know about cancer data to understand these 

results? 

• Cancer registry data does not tell you whether exposure to industrial 

pollutants caused your cancer. 

• Cancer registry data does not contain information about known cancer risk 

factors (family history, diet, etc.) or the type and amount of chemical 

exposures. The lack of this information reduces the ability to associate 

exposures to the development of cancer. 

• More information on individual risk factors and exposure are needed to 

make associations with exposures to cancer. 

From 1990 through 2000, how many people were diagnosed with 

cancer? 

• The North Carolina Central Cancer Registry received reports on 105 people 

who were diagnosed with cancer and who lived within 1 mile of the plants 

located on Jake Alexander Boulevard in Salisbury, North Carolina, . 

What were the most common cancers? 

• The most common cancers diagnosed were 

■ Lung 

■ Breast 

■ Prostate 

■ Colon 

Where any rates elevated within the 1-mile radius of the industrial 

facilities on Jake Alexander Boulevard? 

• No, no cancers were found to be diagnosed at higher-than-expected rates. 

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• When looking at all of the cancers that were diagnosed, overall fewer 

cancers were diagnosed than would be expected. 

• Oral cancer was one specific cancer that was found to occur less often than 

expected. 

What about the cancer rates among residents of Milford Hills? 

• Lymphomas—that is, cancers that begin in cells of the immune 

system—were diagnosed almost five times more often than would be 

expected. 

• Brain cancers were diagnosed almost six times more often than would be 

expected. 

What does this mean for me? 

• Some environmental exposure may have contributed to the increases in 

cancer rates. 

• Without additional information about individual risk factors, exposures, and 

residency, we do not know why there may be an elevated occurrence of 

lymphoma and brain cancers. 

• Because of the very small number of cancers diagnosed the elevated rates 

might not be true. 

• Continue to make healthy lifestyle choices: 

■ Do not smoke 

■ Eat nutritious and well-balanced meals 

■ Get regular exercise 

What additional work is being done? 

• ATSDR will continue to assess the different chemicals that may be in the 

area. 

• The North Carolina Central Cancer Registry will continue to monitor the 

rates of new cancer cases. 

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