After Grace purchased the Libby mine in 1963, the Company implemented a number of programs to protect the health and safety of employees. annual x-rays annual lung function tests employee health questionnaire installation of ventilation equipment increasingly stringent dust control measures, including construction of wet mill to significantly reduce dust levels air sampling ban on hiring smokers anti-smoking campaign at Libby McGill University health studies These efforts resulted in a continued reduction of health risk to all Libby employees. By 1985, the levels of tremolite fiber exposure at Libby were 20 times lower than federal regulations required.