Section 7.2: Setting Prevention Priorities for SWPA
Module 7: Regional Case Example: SW Pennsylvania
The work of cancer prevention narrows with each step. Strong scientific evidence — anchored in evaluations by the International Agency for Research on Cancer (IARC) and the U.S. National Toxicology Program (NTP) — identifies dozens of environmental and occupational agents that cause or contribute to cancer. Regional data show which of those agents are present, where, and at what levels. And community knowledge surfaces the exposures that people actually experience day to day. Where those three sources converge, priorities emerge.
Southwestern Pennsylvania has all three. The CENSWPA Science Companion synthesizes the regional evidence base in detail and serves as the primary reference for the priorities described in this section. This module draws from that document and points back to it for fuller treatment of the science.
Priority-setting in SWPA also requires environmental justice to be central, not adjacent. The communities carrying the heaviest exposure burden — fenceline neighborhoods in the Mon Valley, rural communities in shale-impacted counties, frontline workers in extraction and demolition, and low-income residents region-wide — are also the communities whose voices and experiences should be shaping which priorities are set and how.
The Cancer Burden in SWPA
Setting prevention priorities begins with looking at the data — and looking again to keep current. When CENSWPA reviewed regional cancer incidence drawing on the Pennsylvania Cancer Registry and national surveillance data, the patterns it surfaced shaped the rest of its agenda.
Several environmentally-sensitive cancers — including bladder, lung, leukemia, thyroid, kidney, and breast — were elevated relative to U.S. averages, with the most pronounced elevations in shale-impacted counties (notably Greene and Washington) and along the industrial Mon Valley. Childhood cancer rates in shale counties stood out as a particular concern. In Allegheny County, Black women and men consistently experienced higher incidence than their White counterparts, consistent with the disproportionate exposure to industrial air pollution documented in low-income communities and communities of color across the region. Published regional analyses further made clear that smoking alone could not explain the pattern.
The take-home is twofold. The figures matter — they identify where and for whom the burden is concentrated, which is the starting point for any prevention agenda. And the discipline matters: regular surveillance, structured comparisons, and attention to disparities reveal patterns that overall rates alone would miss. Coalitions elsewhere benefit from the same practice.
SWPA's Priority Exposures
Six priority exposure reduction categories shape SWPA’s environmental and occupational cancer prevention agenda. Each appears on this list because two conditions hold: the science establishes a credible link to cancer (Module 3) — most are designated as known or suspected human carcinogens by the International Agency for Research on Cancer (IARC) and/or the U.S. National Toxicology Program — and regional data show meaningful exposure across SWPA (Module 4), with the heaviest burden falling on communities already shouldering disproportionate environmental and economic stress.
1. Air Toxics from Industrial Sources
Outdoor air pollution is a known human carcinogen, and EPA regulates 71 of its constituents as Hazardous Air Pollutants (HAPs) under the Clean Air Act. In SWPA, the cancer-relevant fraction of the air pollution mixture is dominated by formaldehyde, coke oven emissions, benzene, 1,3-butadiene, hexavalent chromium, naphthalene, and diesel particulate matter — a profile linked to lung, bladder, and leukemia risk in particular.
Allegheny County’s exposure burden is among the highest in the country. EPA’s National Air Toxics Assessment / AirToxScreen data place the county among the worst nationally for cancer risk from HAPs and diesel particulate matter, and worse still for cancer risk from industrial point sources — the great majority of which is attributable to coke oven emissions concentrated at the Clairton facility in the Mon Valley. PennEnvironment’s Toxic Ten analysis tracks the highest-emitting facilities and the specific carcinogens they release.
The burden is also profoundly unequal. Cancer risk from HAPs and diesel particulate in Allegheny County’s environmental justice communities is substantially higher than in non-EJ communities — driven by coke oven emissions and mobile-source carcinogens (benzene, 1,3-butadiene, naphthalene) that fall hardest on the predominantly low-income and majority-Black neighborhoods in the Mon Valley. Air toxics from industrial sources are not just a cancer issue. They are an environmental justice issue.
2. Unconventional Natural Gas Development
Over the last two decades, the build-out of unconventional natural gas extraction across SWPA has introduced a new class of cancer-relevant exposures into rural and exurban communities. More than 200 air pollutants have been measured in association with UNGD activity; nearly two dozen are known or suspected carcinogens, including benzene, formaldehyde, ethylbenzene, fine particulate matter, and naturally occurring radioactive material in drill cuttings and produced water. Drinking water contamination is also a documented concern, with hundreds of confirmed reports of private wells impacted by UNGD activity in Pennsylvania, including in SWPA.
Because cancer is a disease of long latency, the full epidemiological picture for UNGD-associated cancer risk is still emerging. Studies outside Pennsylvania have begun to show associations between UNGD activity and childhood leukemia, and the apparent clustering of childhood osteosarcoma and leukemia in Washington and Westmoreland Counties — and ongoing investigations of its causes — is of significant concern given known links between these cancers and UNGD-associated substances such as radium (bone) and benzene (leukemia). A pilot study has already detected UNGD-associated carcinogens in personal air monitors and the urine of families living near operations in SWPA counties.
This exposure profile is concentrated in counties — notably Washington, Greene, Fayette, and parts of Butler and Armstrong — where rural poverty rates are above state averages and where the legal authority of municipal governments to limit drilling has been constrained. The communities carrying the highest UNGD exposure burden are also among those with the fewest political and economic resources to push back. Like Mon Valley air toxics, UNGD is both a cancer prevention priority and an environmental justice priority.
3. Radon
Radon is a naturally occurring radioactive gas and a known human carcinogen — the second leading cause of lung cancer in the United States. Pennsylvania ranks among the top states nationally for indoor radon, and the Pennsylvania Department of Environmental Protection estimates that roughly 40% of homes in the state have levels above EPA’s action level. SWPA’s geology — particularly its uranium-bearing shales — makes elevated indoor radon a region-wide concern.
The burden of radon exposure is uneven in ways that are easy to miss. Renters cannot easily compel mitigation, and lower-income homeowners may not be able to afford it, leaving exposure unaddressed in households that more economically secure homeowners would resolve. SWPA schools have also been flagged as a radon concern, with testing historically limited. Radon is a cancer prevention priority that intersects directly with housing and education equity.
4. Drinking Water Contamination
Drinking water can carry several established and suspected carcinogens, including chlorination disinfection byproducts (linked to bladder cancer), PFAS (kidney and testicular), inorganic arsenic, hexavalent chromium, and benzene. Disinfection byproducts are unavoidable when chlorine is used to control microbial contamination, but their levels are influenced by source water quality and treatment practices.
In SWPA, public water systems have documented disinfection-byproduct levels above national averages, and contaminants from power plants and UNGD operations are known to influence their formation. Hundreds of confirmed reports of private wells impacted by UNGD have been recorded in Pennsylvania, including in SWPA counties, and PA DEP’s PFAS sampling has documented contamination across the state.
The exposure burden again falls unevenly. Communities served by older municipal infrastructure carry higher disinfection-byproduct risk, and rural households reliant on private wells — particularly in shale-impacted counties — face limited testing access and few enforcement mechanisms when contamination is documented. Drinking water contamination is a cancer prevention priority that tracks existing patterns of geographic and economic inequity.
5. Occupational Exposures
Occupational exposures account for a substantial fraction of preventable cancers and are among the most under-recognized priorities in regional cancer prevention. SWPA’s occupational profile is shaped by the region’s industrial history and current activity. Workers in steel and coke production face coke oven emissions, polycyclic aromatic hydrocarbons, silica, and asbestos in legacy facilities — all classified as carcinogens by IARC. Oil and gas extraction and service workers face BTEX, diesel exhaust, silica from frac sand, and naturally occurring radioactive material. Construction and demolition workers — particularly those involved in legacy-industry cleanup — encounter asbestos, lead, and silica. Migrant and seasonal farmworkers in SWPA’s agricultural counties are exposed to pesticides designated as known or suspected carcinogens, including glyphosate, malathion, and 2,4-D. Healthcare workers face ethylene oxide, antineoplastic drugs, and formaldehyde.
Cancer outcomes linked to these exposures span lung, bladder, mesothelioma, leukemia, non-Hodgkin lymphoma, kidney, and prostate. Long latency periods mean that workers exposed decades ago in legacy operations are still receiving diagnoses today. Occupational cancer risk is concentrated among workers — disproportionately low-income, immigrant, and racial minority — who often lack the protections, surveillance, and political voice that environmental cancer risk in residential settings increasingly receives.
6. Consumer Products
Cancer-relevant exposures also enter homes through consumer products — personal care, cleaning, building, and furnishing items containing chemicals that are absent from most prevention conversations. Hair dyes and chemical hair straighteners have been linked to elevated breast cancer risk, with the strongest signals among Black women, who are disproportionately marketed and exposed to these products. Flame retardants in upholstered furniture, mattresses, and electronics; formaldehyde in pressed-wood building materials; PFAS in carpets, cookware, food packaging, and stain-resistant fabrics; and 1,4-dioxane, parabens, and phthalates in personal care products — all are known or suspected carcinogens whose presence in everyday products is largely unregulated. Moreover, CENSWPA is watching the emerging literature on microplastics which and potential links to cancer, also given the region’s role in propagating the plastics problem – the fracking infrastructure in SWPA is fueling the production of plastic pellets (“nurdles”).
Consumer-product exposures are difficult for individuals to control and disproportionately affect populations targeted by specific product lines or unable to afford safer alternatives. Like other priority exposures, the consumer-product cancer burden falls along familiar lines of race, income, and market structure.
Closing: The priorities
Together, these six priorities define the scope of SWPA’s environmental and occupational cancer prevention agenda. The exposures vary in geography, source, regulatory authority, and the populations most affected — but they share a common pattern: the burden falls hardest on communities and workers with the fewest resources to mitigate it on their own. Section 7.3 turns to the intervention opportunities that follow.