A British lawyer is to bring a group action involving up to 5,000 people in Ivory Coast who claim they were injured by "toxic waste" from a UK-based firm.
Residents suffered headaches, vomiting and breathing difficulties
Martyn Day was given permission to bring the case by a High Court judge.
Trafigura, which has offices in London, has denied the waste it disposed of was toxic, and has begun a libel action against Mr Day's firm.
Ten people died and thousands fell ill after the waste was shipped there and left around the city in August.
A team of six lawyers from the London-based law firm Leigh Day & Co will travel to Ivory Coast, for the second time, on Monday.
Mr Day said he believed 4-5,000 victims in Abidjan would be able to join the claim, provided that they could meet the criteria set out by the judge.
He gave credit to Trafigura for their assistance.
"They have entered into this process in a co-operative spirit which I hope will ensure that the case is brought to a speedy conclusion," he said.
The British lawyers will spend two weeks in the African country, meeting victims at each of the sites where waste was found. With the help of experts they will assess whether people are suffering from long-term damage, said Mr Day.
Most suffered a "grim" few weeks of diarrhoea, vomiting and bloating, he said. Tens of thousands were treated in hospital for nausea, breathing problems and nosebleeds, and many animals in the area died.
"The question is, are there any long term implications?" he told the BBC News website.
He added that they "looked forward" to fighting the libel case brought against them by Trafigura.
Trafigura's director of operations Graham Sharp, said in a statement:
"We were proactive in proposing and agreeing the terms of today's Court Order as we see this as the most expeditious method of dealing with these claims, although we continue to maintain that they are without foundation.
"Trafigura did not 'dump' any waste product in Abidjan where the Company has traded for 10 years and has employees, facilities and long term investments.
"The 'slops' from the Probo Koala's waste tanks were offloaded into road tankers operated by an accredited local contractor under the normal supervision of port, customs and environmental authorities."
The company has said the 480 tonnes of non-toxic "chemical slops" from its gasoline tanker contained spent caustic soda, gasoline residues and water.
The gasoline residues contained high levels of mercaptan - a smelly non-toxic chemical added to natural gas to make it easier to detect leaks, said the firm.
Mr Sharp said they wanted to work with the Ivorian authorities to find out what happened to the waste, which Trafigura said was given over to an accredited company in the city's main port.
He said it was not known whether the waste had been dealt with properly.
When asked if it was possible the waste had later caused ill health among the city's inhabitants he said: "We cannot know ourselves, so in that case it must be possible."
The Ivorian government's slow reaction to the crisis so enraged Ivorians that the cabinet was forced to resign and the government reshuffled.
Local senior officials have also been accused of negligence and corruption.
Trafigura has been ordered to file its defence by 29 June and the case should go to trial early next year.