Impact
Using analytical chemistry to help screen new chemicals and contribute to toxicology science
Each year, more than 2,000 chemicals are introduced for use in commonly used items like food, personal care projects, prescription drugs, household cleaners, and lawn care products, for which approximately 80,000 chemicals are already registered for use.
All of these chemicals are evaluated by the National Toxicology Program (NTP). A unit of the Department of Health and Human Services, NTP is responsible for coordinating toxicology testing of these chemicals and providing information about potentially toxic chemicals to state and federal public health agencies.
In addition to keeping potentially dangerous chemicals out of common products, NTP also advances the science of toxicology by improving testing methods and keeping government agencies and communities up to date and well-informed.
Characterization and Dose Confirmation Help Ensure Accurate, Reliable Results of NTP Studies
Since 1984, we have provided key chemistry services in support of NTP. Our scientists perform chemical analysis in support of the NTP’s research programs, including
- High-throughput screening
- Analytical method development
- Bulk chemical characterization
- Dose formulation development and dose analysis
- Bio sample analysis
- Stability measurements
- Pharmacokinetic studies.
Using reliable sources and comprehensive testing of chemicals to ensure that test substances are fully characterized and free of possible contamination, our chemists help to ensure that NTP studies generate accurate, reliable results about potential effects on public health. Our work continues under a 10-year contract awarded in 2014 to deliver test chemical characterization, dose confirmation, and internal dose determination—critical steps in NTP’s research and testing process.
Our efforts in support of NTP are an example of our ongoing commitment to research of the effects of chemical and environmental exposures on human health. Federal and local agencies rely on NTP to provide the basis for informed decisions about health safety, and NTP, in turn, relies on our analytical chemists, toxicokinetics experts, and researchers.
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.
