A programmable safety unit for monitoring and controlling safety functions of a hazardous environment, for example an environment including hazardous machines, processes, materials, and so forth and safety equipment associated with the hazardous environment. A safety unit is adapted for external mounting, and includes a programmable safety module and a connection part that are interconnectable enabling mounting/demounting and replacement of the programmable safety module and/or the connection part. The safety unit further includes at least two connections that are programmable as safe inputs and/or outputs for direct connection to at least a number of the safety functions or equipment of the hazardous environment, and for example the machines and/or processes.