Human Health Risk Assessments (HHRAs) are essential in toxicology, ensuring products are safe for public use across industries including tobacco, pharmaceuticals, cosmetics, and food. These assessments are often a regulatory requirement and are designed to evaluate potential toxicological risks to humans. Dean Hatt, senior toxicology consultant at Broughton, a testing and regulatory partner, explains that HHRAs involve several stages: Hazard Assessment, Quantitative Risk Assessments (QRAs), and Risk Characterisation. Each industry applies these components according to its specific regulatory and safety needs.
HHRAs begin by identifying harmful substances and assessing their dose-response relationship to determine safe exposure levels. Exposure assessment examines how humans come into contact with a substance, and risk characterisation integrates all findings to evaluate overall safety. According to Hatt, “High-quality data is critical for reliable outcomes, ensuring regulators and manufacturers can trust the results.”
In the nicotine sector, particularly with non-combustible products such as e-cigarettes, the focus is on harmful chemicals that may be inhaled or ingested. Hatt notes that hazard identification compares these products to combustible cigarettes, which helps illustrate reduced risks. When published data is limited, in silico tools are used to predict potential hazards. One significant metric is the Excess Lifetime Cancer Risk (ELCR), which quantifies the cancer risk posed by individual chemicals. This includes ingredients, thermal degradants, and leachables. Such assessments support manufacturers in demonstrating product safety during regulatory submissions.
For pharmaceuticals, HHRAs help ensure that drugs are both safe and effective. Preclinical and clinical studies are used to establish a drug’s therapeutic dose, confirming it does not harm patients at effective levels. Hatt explains that impurities, leachables, and degradation products must also be evaluated to ensure they do not compromise safety or efficacy. Hazard assessments, in silico modelling, and QRAs help define safe levels, supported by in vitro and in vivo studies. Regulatory bodies such as the UK’s Medicines and Healthcare products Regulatory Agency rely on this evidence for market approval.
Cosmetic products are governed by specific HHRA requirements outlined by the Scientific Committee for Cosmetic Safety (SCCS). With animal testing prohibited, a Cosmetic Product Safety Report (CPSR) incorporates the HHRA process. These assessments evaluate factors such as how often the product is used, its concentration, contact time, and skin absorption. Hatt highlights that preservation systems are especially important in maintaining microbial safety. The European Union’s Cosmetics Regulation EC 1223 2009 sets standards that ensure products like moisturisers and lipsticks pose minimal risk to users.
In the food industry, HHRAs address both the contents and the packaging. One key concern is the potential for chemicals to migrate from packaging materials into food products. Each country has its own regulations, but testing is commonly guided by the European Food Safety Authority’s standards. If migration occurs, the HHRA evaluates the safety of these chemicals by calculating margins of safety. Compliance with food contact conformity certification ensures products like canned goods and packaged snacks remain safe for consumption.
QRAs are central to HHRAs across all sectors. They compare exposure levels to toxicological thresholds to determine whether a chemical is considered safe. For nicotine products, this involves assessing inhalation exposure. In pharmaceuticals, it applies to impurities. In cosmetics, the focus is on skin contact. For food, it concerns substances that may leach from packaging. The reliability of these assessments depends on the quality of the data used.
Hatt stresses that “thorough HHRAs are critical across industries, from e-cigarettes to medicines, cosmetics, and food.” These assessments help businesses navigate regulatory demands and ensure the safety of products used by the public every day.
