The London-based oil trader Trafigura faced criminal charges for the first time today, over the environmental scandal which caused international uproar last year and forced it to compensate thousands of Africans made ill by toxic waste.

At the start of a trial in Amsterdam – at which Trafigura is accused of an initial attempt to get rid of the waste cheaply in the Netherlands – prosecutor Look Bougert told the court the company had put "self-interest above people's health and the environment".

He said Trafigura first tried to conceal how dangerous the waste was, then pumped it back on board its tanker and left the Netherlands with hundreds of tonnes of oil residue, contaminated with foul-smelling sulphur mercaptans and toxic hydrogen sulphide.

Instead of paying for specialist disposal, Trafigura "dumped it over the fence" in Abidjan, the main port of poverty-stricken Ivory Coast in west Africa. "Cheap, but with consequences," Bougert said.

Trafigura lawyer Aldo Verbruggen said the charges were based on an unfounded moral judgment. He said: "Trafigura is a company that takes responsible entrepreneurship very seriously." The Dutch charges, if upheld, could lead to a large corporate fine and prison sentences of up to six years for two relatively junior individuals, the tanker's Ukrainian captain, Sergey Chertov, and a London-based Trafigura employee, Naeem Ahmed.

Evert Uittenbosch, director of the Dutch waste disposal firm Amsterdam Port Services, and the Amsterdam city authorities also deny charges of "leaving dangerous waste in the hands of someone not qualified to process it".

It has been ruled that the company's chief executive, Claude Dauphin, should not face personal charges. Nor does the prosecution cover the events after the tanker, the Probo Koala, left Amsterdam, and the subsequent dumping in Abidjan, which sent 30,000 people choking, retching and seeking medical treatment.

Instead, the trial, which is expected to last two months, focuses on the relatively technical question of Trafigura's behaviour in Amsterdam when the tanker made its first attempt to dispose of the contaminated waste. The prosecution says it was misdescribed as routine "slops" from ordinary tank-cleaning. When the disposal company received protests from residents about the foul smell and demanded payment for specialist disposal, Trafigura was allowed instead to pump the waste back aboard and leave the port. It is illegal to export hazardous waste from a European location to be dumped in Africa.

Trafigura gained notoriety last year when it hired British lobbyist Bell Pottinger, and libel lawyer Carter-Ruck, to threaten European media organisations which sought to investigate the firm's behaviour. The company overreached itself and was forced to withdraw, when it attempted to enforce a so-called "super-injunction" against the Guardian, gagging it from reporting proceedings in the British parliament.