Safety system for use with a personal protective equipment for working in great heights comprising: wireless communication means configured to provide a communication with a rescue coordination center; sensor means for providing sensor data comprising at least one acceleration sensor and at least one orientation sensor, wherein the sensor means are located in a separate sensor device attachable to a personal protective equipment; evaluation and notification means configured to determine a fall event and/or a loss of consciousness event based on the sensor data and to notify the rescue coordination center via the wireless communication means by sending an alert event message, a mobile computer device, wherein the sensor device and the mobile computer device comprise communication means, wherein the evaluation and notification means are configured to execute an evaluation algorithm based on the results of a machine-learning algorithm for determining a fall event and/or a loss of consciousness event in real time, wherein the wireless communication means, the evaluation and notification means are located in the mobile computer device, wherein the evaluation and notification means are configured to execute the evaluation algorithm even in case the mobile computer device is in a locked state, standby state or idle state, wherein the safety system further comprises a casing configured to receive the mobile computer device, wherein the casing is made of a material being electrically dissipative, wherein the material of the casing comprises an electrical resistivity of not more than 10 8 Ωm, wherein the material of the casing comprises at least one thermoplastic polyurethane and at least one inorganic filler, or at least one halogen-containing polymer and at least one inorganic filler, or at least one thermoplastic polyurethane, at least one halogen-containing polymer and at least one inorganic filler, wherein the casing is attached or attachable to a personal protective equipment. wireless communication means configured to provide a communication with a rescue coordination center; sensor means for providing sensor data comprising at least one acceleration sensor and at least one orientation sensor, wherein the sensor means are located in a separate sensor device attachable to a personal protective equipment; evaluation and notification means configured to determine a fall event and/or a loss of consciousness event based on the sensor data and to notify the rescue coordination center via the wireless communication means by sending an alert event message, a mobile computer device, wherein the sensor device and the mobile computer device comprise communication means, wherein the evaluation and notification means are configured to execute an evaluation algorithm based on the results of a machine-learning algorithm for determining a fall event and/or a loss of consciousness event in real time, wherein the wireless communication means, the evaluation and notification means are located in the mobile computer device, wherein the evaluation and notification means are configured to execute the evaluation algorithm even in case the mobile computer device is in a locked state, standby state or idle state, wherein the safety system further comprises a casing configured to receive the mobile computer device, wherein the casing is made of a material being electrically dissipative, wherein the material of the casing comprises an electrical resistivity of not more than 10 8 Ωm, wherein the material of the casing comprises at least one thermoplastic polyurethane and at least one inorganic filler, or at least one halogen-containing polymer and at least one inorganic filler, or at least one thermoplastic polyurethane, at least one halogen-containing polymer and at least one inorganic filler, wherein the casing is attached or attachable to a personal protective equipment.