Impact
Using analytical chemistry to help screen new chemicals and contribute to toxicology science
Since 1978, The National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) has worked to protect human health. NTP does research to understand how exposure to chemicals affects people, with a goal of producing scientific information that can support public health decision-makers in preventing diseases. Over time, NTP has become a trusted source of information for government agencies, researchers, and the public. The data and knowledge it produces inform rules, safety standards, and everyday decisions that impact people’s lives.
NTP studies a wide range of substances found in the environment, workplaces, medicines, and consumer products. These studies help answer key questions, such as: Are these substances safe? How do they behave in the body? What risks might they pose over time? By answering these questions, NTP helps decision-makers create better policies that protect human health across the lifespan.
Our Work for the NTP
Sulfolane
This solvent, used in oil refineries, was discovered in drinking water wells near a refinery in Alaska. The NTP chose RTI to study the toxicity of sulfolane with a goal of establishing a threshold of exposure.
Pyriproxyfen
This widely used insecticide targets fleas, ticks, mosquitoes and other pests. Following the 2016 outbreak of the mosquito-borne Zika virus, the NTP and RTI studied its health effects.
MCHM
This foam removes impurities from coal. In 2014, an accidental spill sent more than 10,000 gallons of MCHM into the water supply in Charleston, West Virginia, leaving 300,000 people without water for days. Although little was known about the health effects of MCHM at the time, local emergency departments saw a dramatic increase in visits. RTI helped NTP learn more about how MCHM causes skin sensitivity and irritation.
Brominated Flame Retardants
Baby products, furniture, electronics, vehicle interiors, and construction materials often contain flame retardants designed to protect people from injuries and property loss. These chemicals are very effective at stopping fires. However, some types have adverse health effects that are not well understood. RTI developed a method of studying flame retardants containing bromine, enabling easier measurement and better-informed regulation.
Organotin Compounds
Organotins are a class of compounds containing tin bound to carbon atoms. These are highly useful in industrial applications and household products, but were phased out of boat paint — previously one of their most widespread uses — because they can be toxic to marine wildlife, and accumulate throughout the food chain.
Using data from an existing study of environmental exposures in expectant mothers, along with a method we developed a for analyzing organotins in serum, we helped NTP lay the groundwork for future biomonitoring studies of similar contaminants.
Carbon Nanotubes
Highly durable and versatile, carbon nanotubes are an increasingly popular material in everything from next-generation supercapacitors to fibers and fabrics. Beyond the unknowns about nanotubes' environmental and health effects, there are questions around nanotube production, including workers who are exposed to these materials during manufacturing, and aerosols released by production facilities.
RTI’s analytical laboratories analyzed the purity, composition, and dimensions of different carbon nanotubes for NTP’s studies. This contributed to the 2018 establishment of appropriate exposure controls for nanotube production workers.
Hexavalent Chromium
Public awareness of the harms of hexavalent chromium in drinking water increased in the early 2000s, amid widespread media coverage of exposure clusters such as the one depicted in the movie Erin Brockovich. When the NTP and Environmental Protection Agency investigated how chromium spreads through the body, potentially causing cancer, RTI provided essential analytical chemistry services. This directly informed ongoing regulations of chromium exposure.
Senna
Botanical supplements are another source of potential chemical exposures for many U.S. consumers. People think of them as "natural" and beneficial, but because they are regulated as foods rather than drugs, they are often poorly studied and can contain undisclosed contaminants such as pesticides and metals.
Senna is a common dietary supplement used as a laxative. The Food and Drug Administration enlisted RTI's help to identify constituents in senna powder for pre-clinical toxicity studies. The resulting studies found that while senna is not linked to cancer, it can damage the gastrointestinal tract when overused. This finding provides safety guidance to the FDA, health care providers, and consumers.
Why is the National Toxicology Program Important?
People can be exposed to any of tens of thousands of chemicals every day in water, air, food, or products used at home or at work. Without reliable science, it would be difficult to know which exposures are safe and which could cause harm. NTP fills this gap by producing high-quality, trusted data that can guide science-based decision making. Its research is carefully designed to ensure the results are accurate and reliable, drawing on state-of-the-science technology and methods to gain insights into what these chemicals do to the human body. Some applications that NTP’s work has helped support include:
- New public health goals for chemicals found in drinking water
- Updates to safety lists that identify harmful substances
Better understanding of emerging issues like PFAS (“forever chemicals”), microplastics, and complex mixtures of substances
These actions turn science into practical knowledge that helps people stay safe and protects communities from long-term health problems.
