According to ILO Convention No. 171 (1990), the term “night work” means all work performed during a period of not less than seven consecutive hours, including the interval from midnight to 5 a.m., to be determined by the competent authority after consulting the most representative organizations of employers and workers or by collective agreements. The term “night worker” means an employed person whose work requires performance of a substantial number of hours of night work that exceeds a specified limit. This limit shall be fixed by the competent authority after consulting the most representative organizations of employers and workers or by collective agreements. Convention No. 171 applies to all employed persons except those in agriculture, stock raising, fishing, maritime transport and inland navigation. An ILO member State that ratifies this Convention may exclude, wholly or partly from its scope, limited categories of workers when the application of the Convention to them would raise special problems of a substantial nature. Specific measures required by the nature of night work shall be taken for night workers in order to protect their health, assist them in meeting their family and social responsibilities, provide opportunities for occupational advancement, and compensate them appropriately. Such measures shall also be taken in the fields of safety and maternity protection for all workers performing night work. At their request, workers shall have the right to undergo a health assessment without charge and to receive advice on how to reduce or avoid health problems associated with their work: (1) before taking up an assignment as a night worker; (2) at regular intervals during such an assignment; (3) if they experience health problems during such an assignment that are not caused by factors other than the performance of night work. With the exception of a finding of unfitness for night work, the findings of such assessments shall not be transmitted to others without the workers’ consent and shall not be used to their detriment. Suitable first-aid facilities shall be made available for workers performing night work, including arrangements whereby such workers, where necessary, can be taken quickly to a place where appropriate treatment can be provided. Night workers certified, for reasons of health, as unfit for night work shall betransferred, whenever practicable, to a similar job for which they are fit. If transfer to such a job is not practicable, these workers shall be granted the same benefits as other workers who are unable to work or to secure employment. A night worker certified as temporarily unfit for night work shall be given the same protection against dismissal or notice of dismissal as other workers who are prevented from working for reasons of health. Measures shall be taken to ensure that an alternative to night work is available to women workers who would otherwise be called upon to perform such work: before and after childbirth, for a period of at least 16 weeks of which at least eight weeks shall be before the expected date of childbirth; for additional periods in respect of which a medical certificate is produced stating that it is necessary for the health of the mother or child: during pregnancy; during a specified time beyond the period after childbirth fixed pursuant to paragraph (a) above, the length of which shall be determined by the competent authority after consulting the most representative organizations of employers and workers. The measures may include transfer to day work where this is possible, the provision of social security benefits or an extension of maternity leave. Compensation for night workers in the form of working time, pay or similar benefits shall recognize the nature of night work. Appropriate social services shall be provided for night workers and, where necessary, for workers performing night work. Before introducing work schedules requiring the services of night workers, the employer shall consult the workers’ representatives concerned on the details of such schedules and the forms of organization of night work that are best adapted to the establishment and its personnel, as well as on the occupational health measures and social services that are required. In establishments employing night workers this consultation shall take place regularly. See: Night work (women); Night worker