Chimpanzees that were once used in experiments for the hepatitis B vaccine are now receiving comprehensive health checkups at a sanctuary in Liberia. Many of these chimpanzees were captured from the wild as infants and were used in research conducted by American scientists in Liberia from the 1970s through the early 2000s. Today, they reside at the Second Chance Chimpanzee Refuge, run by Humane World for Animals, located in central Liberia. The sanctuary is situated on a series of islands covered in mangrove forests, offering a more natural habitat for the chimps. Liliana Pacheco Ricote, the director of the sanctuary, told The Associated Press that more than 400 chimpanzees were used in the research. In 2015, Humane World for Animals took over the care of 60 of these chimpanzees who remained after the research program ended. The health assessments now being conducted include a variety of procedures, such as teeth cleaning, X-rays, and even pedicures. These exams, performed under anesthesia, are designed to evaluate the long-term health of the chimps, detect any early signs of illness, and create individualized care plans as they age. The tests also include examinations of the heart, lungs, and nervous system, along with blood tests and booster vaccinations. The full impact of the experiments on the chimpanzees, who are now between 30 and 35 years old, remains unclear. The results of the health assessments are still being analyzed, and the sanctuary plans to continue these evaluations for the remaining chimpanzees. This ongoing process is crucial for understanding the long-term effects of the research and ensuring the chimps receive the best possible care in their later years. West Africa is home to a significant population of chimpanzees, with Liberia having the second-highest number after Guinea. However, the species is classified as critically endangered due to a sharp decline in their numbers. This decline is driven by factors such as habitat loss, poaching, and human encroachment. The sanctuary's efforts to care for these chimpanzees not only provide them with a better quality of life but also highlight the importance of conservation and ethical treatment of animals used in research.