Indiana Code Title 22. Labor and Safety § 22-3-3-1

Sec. 1. Unless the employer or his representative shall have actual knowledge of the occurrence of an injury or death at the time thereof or shall acquire such knowledge afterward, the injured employee or his dependents, as soon as practicable after the injury or death resulting therefrom, shall give written notice to the employer of such injury or death.

Unless such notice is given or knowledge acquired within thirty (30) days from the date of the injury or death, no compensation shall be paid until and from the date such notice is given or knowledge obtained.  No lack of knowledge by the employer or his representative, and no want, failure, defect or inaccuracy of the notice shall bar compensation, unless the employer shall show that he is prejudiced by such lack of knowledge or by such want, failure, defect or inaccuracy of the notice, and then only to the extent of such prejudices.