MV Carrier: Fuel pumped off Llanddulas ship at low tide
About 20,000 litres of fuel has now been removed from the stricken cargo ship off the north Wales coast.
Contractors have to remove all 24,000 litres of the gas oil before work can start on scrapping the MV Carrier at Llanddulas, near Colwyn Bay.
The ship's owners say it has been "declared a constructive total loss" after running aground last Tuesday.
Environment Agency Wales said on Sunday its staff are monitoring progress and taking samples during the operation.
A spokeswoman said the work to remove the fuel is taking place during low tides.
The next meeting of all parties involved in the ship's removal is due to take place on Tuesday.
Seven Polish crew had to rescued when the vessel encountered difficulties.
Two lifeboats and Royal Navy and RAF helicopters were involved during the night-time rescue in heavy seas.
Workers from PGC Demolition of Heywood, Lancashire, are pumping the fuel into containers on the shore line before they start to cut the vessel into manageable sections.
It will then be taken by road to a designated scrap yard, according to German shipping firm Reederei Erwin Strahlmann, which owns and manages the vessel.
It has said a structural assessment revealed severe damage so the vessel has been "declared a constructive total loss".
The operation to remove fuel from the vessel began on Thursday.
The Maritime and Coastguard Agency (MCA) is also involved in the operation.
An investigation into the incident has been launched by the Department of Transport's Marine Accident Investigation Branch.
A 40mph speed limit has been imposed on the adjacent A55 expressway.