This part of ISO 11681 deals with the significant hazards and specifies safety requirements and their verification for design and construction of portable combustion-engine, hand-held chain-saws, designed only for use by one operator and intended for forest work. It describes methods for the elimination or reduction of hazards arising from their use. In addition it specifies the type of information on safe working practices to be provided by the manufacturer. It deals with all significant hazards. It does not cover the hazard from kickback for machines with an engine displacement over 80 cm3. The environmental aspects, except for noise, have not been considered. Chain-saws covered by this part of ISO 11681 are designed for use by persons having read and understood the safety requirements in the instruction handbook and using the appropriate personal protective equipment (PPE). The chain-saws covered are designed only to be operated with the right hand on the rear handle and the left hand on the front handle. This part of ISO 11681 is not applicable to chain-saws which are manufactured before the date of publication of this document.