On Tuesday, hundreds of the city's residents threw up barricades in protest, prompting the government to appeal on national television for roads to be cleared so that medical personnel could get through. The waste is residue from gasoline cargo shipped to Abidjan's port last month.

Local newspapers this week reported that two children died after inhaling the toxic fumes.

In a bid to reassure the population, health officials appeared on state television late Tuesday to say the government was trying to locate the sites where the waste had been discharged.

"Indeed, the waste consists of toxic products," said Health Minister Remi Allah Kouadio, adding that the government was considering supplying local hospitals with medication.

Hundreds of people had turned up at local hospitals, some with complaints ranging from eye irritation to nausea, while others were desperately seeking information about the nature of the waste following rumours that it was radioactive, a health official told IRIN on condition of anonymity.

Local media reports about the waste began appearing last week as residents complained of a pervading noxious odour emanating from several different neighbourhoods, including the city's main garbage dump.

Protests began on Monday near the garbage disposal site and the city zoo, with scores of people barricading roads to stop tanker trucks and brandishing placards accusing the government of negligence.

"We have been living with this horrible smell for two weeks and it is making us sick," said Guy Roland, a young resident of Plateau Dokui, one of the affected neighbourhoods. "We are asking the authorities to do something."

After gasoline from the Netherlands-based commodities trading firm Trafigura Beheer B.V. was unloaded two weeks ago a local company specialising in chemical waste disposal was charged with getting rid of the residue, according to Trafigura.

The waste contains the strong-smelling chemicals hydrogen sulphide and mercaptan, according to a report by the Ivorian Anti-Pollution Centre (CIAPOL), obtained by IRIN.

The report says hydrogen sulphide is "a toxic substance that can lead to immediate death when inhaled".

In a statement, Trafigura said it was "very concerned that the residue of the ship... has been disposed of inappropriately in Abidjan".

Trafigura Beheer B.V. is the holding company of Trafigura Group, a leading independent commodities trading company specialising in petrol, gasoline and base metals. (Editors Note: Netherlands based Trafigura Group, one of the world's top trading companies. Established in 1993, Trafigura now employs more than 630 people in 58 offices in 46 countries worldwide. In 2004 turnover exceeded $17.5 billion. Group equity now stands in excess of $500 million.)

The company confirmed in a statement that the cargo had been gasoline, containing a mixture of petrol and sulphur, with an added concentration of sulphuric products. It said it had informed authorities about the nature of the waste and had sent a written request that it should be safely discarded.

The company declined requests for an interview.