SAN JUAN, Puerto Rico (AP) — An offshore oil spill that prompted Trinidad and Tobago to declare a national emergency earlier this month has reached the shores of the Dutch Caribbean island of Bonaire hundreds of miles away, authorities said. This is the first sign of how far the leaked oil has traveled.

Government officials said the oil poses a “serious threat” to the island and its nature including its mangroves, fish and corals. The oil washed up in areas along Bonaire’s east coast despite efforts to contain it, the government statement said Monday.

Bonaire is more than 500 miles (830 kilometers) east of Tobago, where the spill occurred.

Officials have said they don’t how much oil has leaked or remains on board.

The oil is leaking from an overturned barge that had departed from Panama and was being tugged to nearby Guyana when it began to sink, according to a preliminary investigation. The owner of the barge has not been identified.

Trinidad and Tobago’s Ministry of Energy said Tuesday that crews completed an investigative hydrographic survey of the wreck to allow officials to create a map of the seabed and other data around the wreck, which foreign experts are helping to remove.

Crews are working to contain and collect the oil, officials said.

Environmental activists have questioned who will pay for the cleanup costs and demanded help for fishermen whose livelihood and equipment were affected.