There's been (an event)

You use "There's been a ___" to describe an important event that has happened. For example:

There's been a murder.

There's been an earthquake in San Francisco.

oil spill

An "oil spill" is when a large amount of oil leaks out into the ocean from a crashed oil tanker (a boat that carries oil), a broken oil pipeline, or from an offshore drilling location.

off the coast of (somewhere)

This phrase describes a location in the ocean that's away from the land but close to a certain continent, country, state, province, island, etc.:

off the coast of South America

off the coast of Maui

off the coast of California