Ee reported to NGM on 5/4/26 that on 4/3/26 ee was working 'in EE's columns' when a contractor and crew started hydro blasting above EE, causing debris to fall onto EE. EE reports that EE and a coworker yelled and went to the control room. Injury not reported to NGM until 5/4/26. No signs of injury to ee. Site cannot confirm incident occurred as reported by ee.