Ivory Coast has begun to make safe 11 sites contaminated by toxic waste which killed at least seven people and led to the resignation of the cabinet.
The waste is a mixture of caustic washings, gasoline and water
Thousands of people queued at hospitals and health centres to get treatment for symptoms related to the toxic fumes.
A French company is carrying out the clean-up operation, which is expected to take two weeks.
The clear-up began at Abidjan's main rubbish dump, the site worst affected by the foul-smelling sludge.
"Technically it is not very easy, we are talking about toxic waste so we have to be very careful," said Francois Salbaing, from France's Seche group.
The 400 metric tonnes of waste contained a mixture of gasoline, water and caustic washings.
The government's slow reaction to the crisis so enraged Ivorians that the cabinet was forced to resign and the government reshuffled.
Many thousands of people have sought treatment for vomiting, stomach pains, nausea, breathing difficulties, nosebleeds and migraines.
The company which chartered the ship which transported the waste, Trafigura Beheer BV, says it informed the Ivorian authorities that the waste should be disposed of correctly.
An inquiry is under way and eight people have been arrested so far.