Estimates show that up to 500,000 people living in the Combeima, Chinchina, Coello-Toche, and Guali valleys are at risk, with 100,000 individuals being considered to be at high risk. Lahars pose a threat to the nearby towns of Honda, Mariquita, Ambalema, Chinchina, Herveo, Villa Hermosa, Salgar and La Dorada. Although small eruptions are more likely, the two-million-year eruptive history of the Ruiz–Tolima massif includes numerous large eruptions, indicating that the threat of a large eruption cannot be ignored. A large eruption would have more widespread effects, including the potential closure of Bogotá's airport due to ashfall.