Toxic Substances, Lasting Health Impacts
Understanding the risks of toxic substances and finding safer alternatives
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People encounter thousands of chemicals and other substances in their daily lives through the air they breathe, the water they drink, the food they eat, and the products they use. While many substances have improved quality of life, some have been linked to adverse health effects, including developmental disorders, reproductive health impacts, cancer, respiratory disease, and other chronic conditions.
Scientific understanding of toxic substances continues to evolve as researchers learn more about how exposures affect human health. In many cases, exposures occur long before health effects become apparent. Some substances may accumulate in the body or the environment, while others may be especially harmful during critical stages of development, such as pregnancy, infancy, and childhood.
For more than two decades, we have examined toxic substances and their potential impacts on human health. Through research, education, and policy engagement, we work to help individuals, communities, and policymakers better understand environmental risks and opportunities for prevention.
Why It Matters
People are exposed to a wide variety of chemicals through consumer products, food packaging, household furnishings, building materials, pesticides, drinking water, and industrial activities.
Many substances have undergone extensive safety testing, but others remain the subject of ongoing scientific investigation. Emerging research continues to identify chemicals that may affect human health even at low levels of exposure.
Certain populations may be particularly vulnerable, including pregnant women, infants, children, older adults, and individuals with pre-existing health conditions.
Reducing unnecessary exposures and promoting safer alternatives can help protect public health while encouraging innovation and responsible chemical management.
What You Should Know
PFAS ("Forever Chemicals")
PFAS are a large group of human-made chemicals used in products such as non-stick cookware, stain-resistant fabrics, food packaging, and firefighting foams. Because they break down very slowly, PFAS can accumulate in water, soil, wildlife, and people. Research has linked certain PFAS exposures to developmental effects, immune system impacts, reproductive concerns, and increased risk of certain diseases. Learn more at these websites: EPA, NIEHS, ATSDR
Endocrine-Disrupting Chemicals
Certain substances, including BPA, phthalates, and some pesticides, may interfere with the body's hormone systems. Researchers continue to study how these chemicals may affect development, reproduction, metabolism, and other biological processes. Learn more at these websites: NIEHS, WHO, Endocrine Society
Pesticides and Consumer Product Chemicals
People may encounter pesticides and other chemicals through food, homes, schools, lawns, and workplaces. Exposure levels vary, but reducing unnecessary exposure can be an important part of a preventive public health strategy. Learn more at these websites: EPA, NIEHS, AAP
Toxic Substances Are Not Always Visible
Many potentially harmful substances cannot be seen, smelled, or tasted. Scientific testing, monitoring, and research are often necessary to identify risks. Learn more at these websites: CDC, EPA, ATSDR
Prevention Matters
Many exposures can be reduced through informed consumer choices, safer products, improved environmental standards, and science-based public policies. Learn more at these websites: EPA (Healthy Homes), EPA (Children’s Environmental Health), AAP, NIEHS
Our Work
EHHI has examined a wide range of toxic substances and their impacts on human health.
Areas of work have included:
- PFAS and emerging contaminants
- Endocrine-disrupting chemicals
- Plastics and chemical additives
- Pesticides
- Consumer product safety
- Chemical policy
- Environmental exposures affecting children and families
Through reports, educational materials, policy recommendations, and public outreach, EHHI has worked to increase awareness of chemical exposures and opportunities for prevention.
Featured Resources
Please download and read these important publications.
Our Recommendations
Protecting public health from toxic substances requires action by individuals, businesses, researchers, and policymakers.
National Government
- Strengthen chemical safety review programs.
- Improve monitoring of emerging contaminants.
- Increase transparency regarding chemical ingredients and health effects.
- Support independent environmental health research.
State & Provincial Government
- Improve chemical disclosure requirements.
- Reduce exposures in schools and public buildings.
- Strengthen drinking water protections.
- Promote safer alternatives to hazardous substances.
Local Government
- Support local environmental monitoring programs.
- Encourage safer purchasing policies in schools and municipalities.
- Expand public education about toxic exposures.
- Participate in environmental health initiatives.
Individuals
You can help reduce exposure to toxic substances by:
- Reading product labels and safety information.
- Limiting the use of plastics for food storage and heating.
- Testing drinking water when appropriate.
- Following pesticide safety recommendations.
- Properly disposing of hazardous household products.
- Supporting science-based policies that protect public health.
- Participating in public comment opportunities related to environmental health decisions.
- Download our Fast Look Checklists for toxic substances.
Current Developments
Explore these authoritative websites for the latest developments in toxic substance research, policy developments, and environmental health issues.
- PFAS Regulations Continue to Evolve: Federal and state agencies continue updating standards for PFAS in drinking water and consumer products. Visit Nature.
- New Research on Endocrine-Disrupting Chemicals: Researchers continue examining BPA, phthalates, and related chemicals. Visit MPDI.
- Chemical Safety Policy Updates: Agencies continue evaluating chemicals used in consumer products and industry. Visit Yale.
Frequently Asked Questions
What are PFAS and why are they called "forever chemicals"?
PFAS are a group of synthetic chemicals that persist in the environment and the human body for long periods of time. Visit EPA and ATSDR to learn more.
What are endocrine-disrupting chemicals?
These are substances that may interfere with the body's hormone systems and affect normal biological processes. Visit NIEHS and WHO to learn more.
How are people exposed to toxic substances?
Exposure can occur through air, water, food, consumer products, workplaces, and the broader environment. Visit ATSDR and CDC to learn more.
Can individuals reduce exposure to toxic substances?
Many exposures can be reduced through informed choices, safer products, healthful home environments, and awareness of environmental risks. Visit EPA, AAP, and NIEHS to learn more.
Download our Fast Look Checklists for toxic substances.