US Coast Guard investigates fuel spill off the tiny Puerto Rican island of Vieques

SAN JUAN, Puerto Rico — The U.S. Coast Guard on Saturday investigated a fuel spill off the tiny Puerto Rican island of Vieques, which is popular with tourists.

A mile-long sheen and a strong diesel odor was reported by local emergency medical officials on Friday afternoon along Sun Bay Beach, which is known for its clear, turquoise waters.

At least one person was exposed to the unknown substance and received treatment, the Coast Guard said Friday.

Authorities urged people to stay out of the water.