This Recommendation provides guidelines and requirements for techniques to enable optically safe working conditions (for the human eye and skin) on optical interfaces of the Optical Transport Network, in particular, for systems employing high-power Raman amplification techniques, for equipment in restricted and controlled locations. Because of revisions of relevant IEC requirements, the ALS procedure, defined in a previous version of this Recommendation for SDH systems, is no longer necessary and has therefore been moved to an informative appendix. Furthermore, this Recommendation provides new guidelines on APR procedures for systems employing high-power Raman amplification techniques.