The invention relates to a machine for material processing with a laser beam, in particular laser welding. It is comprised of a machine guided protective housing with an outlet opening surrounding the laser beam that is pointed at the material during processing.To create a machine for laser beam welding which ensures improved operator and personal safety without completely enclosing the machine, it is suggested that the protective housing contains at least one sensor which measures certain chemical or physical properties. The sensor is connected to the machines control unit which compares the current values with reference values for a measure and, depending on current/reference value comparison, interrupts the laser beam or prevents laser beam activation. In addition a method and arrangement for improved operator and personal safety for operation of such a machine is presented.