The science is clear: dozens of chemicals found in indoor and outdoor environments contribute to cancer. This evidence is based on comprehensive reviews by authoritative scientific bodies, including the World Health Organization’s International Agency for Research on Cancer (IARC) and the U.S. National Toxicology Program (NTP).
The Science
Understanding Environmental Cancer Risks in Southwestern Pennsylvania
CENSWPA's Scientific Reviews
Science Companion: Regional Cancer Risks
CENSWPA’s Science Companion reviews the state of the science related to the contribution of environmental and occupational chemicals to cancer, with a specific focus on risk factors that are elevated in Southwestern Pennsylvania.
Year in Review - Research Briefs
CEN issues a monthly Digest, which includes a list of recently published research articles. Each year, the Science Hub reflects on the collection of articles and publishes a Year in Review – Research Brief. Below are the topics addressed. More recent Briefs also detailed summaries not just about the science of harm, but prevention opportunities.
2025: Expanding evidence on cancer pathways and exposures
- Air pollution linked to a broader range of cancers, including breast, bladder, and blood cancers.
- Endocrine-disrupting chemicals implicated in cancer through multiple biological pathways.
- Microplastics with emerging evidence of cancer-related effects.
- PFAS (“forever chemicals”) associated with increasing numbers of cancer types.
2024: Emerging populations and systemic effects
- Rising rates of cancer in young adults raise concern about environmental contributors.
- Microplastics associated with potential cancer risks beyond presence in the body.
- PFAS linked to an expanding range of cancers.
- Environmental exposures affecting cancer severity and survival outcomes.
2023: Built environments and upstream prevention
- Childhood cancer risks linked to unconventional natural gas development, agricultural chemicals, and air pollution.
- Environmental injustice as a driver of cancer risk disparities.
- Cancer risks and prevention opportunities embedded in the built environment.
- Endocrine-disrupting chemicals and opportunities for safer consumer product choices.
2022: Regional evidence and equity implications
- Pennsylvania studies linking air pollution to cancer survival and fracking to increased cancer risk.
- Air pollution associated with cancers beyond lung cancer.
- Environmental injustice associated with elevated cancer risk.
- Childhood cancer risks linked to pesticides and air pollution.
2021: Emerging signals and research gaps
- Air pollution linked to cancers beyond lung cancer.
- Childhood cancer risks associated with pesticides and air pollution, with key research gaps remaining.
- Emerging contaminants, including PFAS, linked to cancer risk.
- Limited evidence on interventions to reduce environmental cancer risks.
CENSWPA’s Cancer Risk Reduction Priorities
In the case of environmental chemicals, exposure to a single pollutant may only slightly increase risk of cancer for one individual. However, the impact changes when that exposure is widespread. When an entire community is exposed to a pollutant—or multiple pollutants—those small individual risks add up to a significant number of cancer cases in the general population.
These environmental chemicals contribute to cancer risk in Southwestern Pennsylvania. Assessment of exposure—an important component of risk—is limited for some of these risk factors; for others, we know that exposure is higher in our region than elsewhere. Reducing exposure to chemicals or pollutants known to contribute to cancer is an important and often overlooked strategy for cancer prevention.
Air Pollution
Allegheny ranks among the worst 4% of counties nationwide with regard to estimated cancer risk from exposure to hazardous air pollutants (HAPs) and Diesel Particulate Matter (DPM). This does not include the cancer risk from fine particulate matter.
Fracking-Related Pollution
Carcinogens released and formed during the process of fracking natural gas include benzene, formaldehyde, particulate matter, and radioactive compounds threaten the wellbeing of residents in a number of counties in SWPA. Studies have shown that children living closer to oil and gas wells have higher rates of leukemia.
Pesticides
Some chemicals used in agriculture, in homes and gardens, on golf courses, playing fields, parks and in buildings are known carcinogens; others disturb biological processes that normally project against cancer. Early life exposures to pesticides used at home are tied to leukemia and brain tumors in children, as are parental exposures. A recent review of 40 studies concluded that documented use of pesticides was associated with brain cancers in farmers.
Radon
Pennsylvania ranks third among all states for levels of radon–roughly 40% of homes have radon above EPA’s action levels. Radon is the second leading cause of lung cancer in the US.
Toxic Chemicals in Consumer Products
Chemicals known to cause cancer are in a range of consumer products, including cosmetics, furniture, building materials, and home and garden pest control products, despite availability of safer alternatives.
Water Pollution
Drinking water in our region has been contaminated by radioactive and other hazardous substances, including from fracking activities.