In 1985, Voight blamed human error for the Armero tragedy in Colombia, where more than 23,000 died from an eruption from the Nevado del Ruiz volcano. He stated that while categorically accurate predictions of volcanic eruptions were impossible, unpreparedness for the disaster exacerbated the death toll. In January 1986, Voight visited Nevado del Ruiz responding to concerns from the Colombian government that the northeastern section of the volcano might cave in, causing another eruption. He established a monitoring network of reflectors and used laser ranging to track how the distances to these reflectors changed over time.