More than a week after crews discovered the leak, oily water continued to spill into Port Valdez on Monday. Responders report that the spill is contained by boom.

Cleanup crews on Monday continued to skim oil off the water near a small boat harbor at the Valdez Marine Terminal, where Alaska oil is loaded onto oceangoing tankers. They continued digging through snow and earth to stop the flow of oily water.

The pollution is primarily entering the water at a rocky area near the low tide line, which suggests oil has flowed below the ground, according to a statement from the incident management team on Monday.

A drain area about a quarter mile uphill from the coast is the source of the polluted liquid, the team said.

The leak was first reported on Sunday, April 12, when crews spotted a sheen on the water. Booms strung atop the water have contained the oil near the harbor since then. More than 230 people are responding.

Flights over the port show the “impacted area is decreasing," the team said.

Snow removal crews cleared an “area of interest” near an oil-spill response building. They are digging out an area uphill of the building to create a potential collection point to capture the oily liquid before it reaches the water, the team said.

Cleanup crews have removed 798 barrels of oil and seawater mixture as of Monday afternoon, the team reported.

“Collection rates are starting to reflect the decline in contaminated fluid that is entering Port Valdez since the point of origin was secured,” the team said.

Crews have measured and analyzed about three-quarters of the recovered oil and seawater mixture. About 12 barrels of oil were contained in that mix, according to an ongoing analysis. The total amount of oil spilled is not currently known.

The cause of the spill remains under investigation. Tests performed over the weekend verified that the oil is not from a pipeline, the statement said.

Complicating the response has been a thick layer of wet snow, partly frozen earth and underground facilities that require careful excavation to halt the flow of oil downhill, the team has said.

Clarification: An earlier version of the story said the spill is “almost entirely” contained by boom, but the spill is currently entirely contained by boom, according to the incident management team. The incident management team was referring to the entire duration of the spill response — some oil has appeared outside of the boom over the course of the spill.