The evacuation of El Paso was ordered after lava started spewing from a new crack in the Cumbre Vieja volcano.
More than 6,000 people have fled from lava that has buried hundreds of homes since the eruption began on Sunday.
Four earthquakes hit the island shortly after the new eruption vent opened.
Local officials said the lava could trigger a chemical reaction that causes explosions and the release of toxic gasses when it reaches the sea.
Marine authorities have established an exclusion zone of two nautical miles (3.7km) at sea, in the area where the lava is heading.
This was done "to prevent onlookers on boats and prevent the gases from affecting people", the president of the island's council, Mariano Hernández, said.
Experts told local media the lava is expected to reach the sea at about 12:00 (11:00 GMT) on Tuesday. Residents have been told to stay away from the area, which has been cordoned off by police.
In the meantime, the lava continues to advance down the volcano's western flank, destroying everything in its path.
As of Tuesday morning, the lava had covered 103 hectares (1 sq km) and destroyed 166 houses, the EU's Copernicus service estimated. A satellite image showed the lava's path down the mountain.
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