This study aims to determine and evaluate the toxicity characteristics of Ahlat stone and pumice, which are pyroclastic rocks specific to Nemrut Volcanism and are common construction materials in the region. There are several studies in the literature that deals with constructional properties, but environmental properties have not been evaluated yet. Behaviour of Pyroclastic rocks due to the environmental conditions are important because pyroclastic rocks contain heavy metals (lead, chromium arsenic, etc.) in their structures due to geological activities. Depending on environmental conditions, these heavy metals can be released from the rock structure and cause hazardous health problems in people who contact them. This situation is directly related to the stability of the rock structure. The TCLP procedure was applied in this study to determine the stability of the rock structure and to determine the potential effect of heavy metals released from the structure on human health and the results obtained were evaluated. The obtained XRF results show that the different colored examined Ahlat stones consist mainly of SiO2, Al2O3, K2O, and Fe2O3 compounds.TCLP results show that the materials are in stable structures, they are not affected by environmental conditions and the amount of heavy metal leakage from structures is very low. However, chromium and arsenic in volcanic areas can have a carcinogenic effect on children. For this reason, a comprehensive soil and water pollution monitoring and analysis study is recommended in the volcanic area for public health.