Claims for benefits under this chapter shall be barred unless notice of injury is given to the employer within 2 years from the date of the injury; provided, however, that if the nature of the injury and its possible relationship to the employment are not known to the employee, the time for filing notice shall not begin to run until the earlier of the following:
RSA 281-A:19
1988, 194:2, eff. July 1, 1989.