A federal agency says it is investigating the death of a worker who on Tuesday fell 12 feet to a concrete floor at an East Hampton construction site.

The worker, Vitor Nobre, 55, of Ronkonkoma, employed by N & D Masonry Corp., also of Ronkonkoma, lost his footing and fell at the site on Further Lane at 8:43 a.m., according to East Hampton Village police.

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A spokesman for the Occupational Safety and Health Administration said Thursday an investigation into the workplace accident began later Tuesday.

OSHA is the main federal agency that investigates job-related accidents to determine what safety standards apply and whether companies have followed those standards.

The agency spokesman said N & D Masonry is a subcontractor; the general contractor for the construction project is Bulgin & Associates Inc., a custom homebuilder based in Southampton.