The background: The residues are filtered soot that had been produced during the gasification of heavy oil at Shell's Wesseling plant, so-called petroleum coke, also known as oil pellets. These can either be burned or stored in landfills. In July 2019, the Ministry of the Environment and the district government of Cologne reassessed the substance: since then, it is no longer considered a fuel, but waste. This is because, compared to conventional petroleum coke, it contains a higher proportion of the heavy metals vanadium and nickel. These are potentially carcinogenic and harmful to the environment.

"According to the previous approval situation, Shell's filtered soot was a fuel, and the refinery has behaved in accordance with applicable permits," explains Shell press spokesman Mauritz Faenger-Montag at the request of the GA. Immediately after the reassessment in July, Shell had declared that the soot "will be treated as hazardous waste in the future". After the plant, which had been shut down for maintenance in July, had been restarted, the same procedure had been followed. For further treatment, this meant that a company commissioned by Shell had no longer sold the material for incineration, but only to landfill sites.

Shell petroleum coke was supplied to companies in 20 NRW cities. According to a report by NRW Environment Minister Ursula Heinen-Esser in October 2019, the emission values were not exceeded at two of the companies investigated, which had incinerated the residues. "The report (...) indicates that the official inspection did not reveal any indications that the limit values applicable to the respective plants had been exceeded," emphasises Shell press spokesman Faenger-Montag.

The report describes the period during which Shell sold the carbon black. According to the report, the ministry has data from the purchasers of the residues until 2008. For the period before that, starting from the year 2000, the data is incomplete due to expired retention periods. According to the reply to the small inquiry, the purchasing companies knew the heavy metal content of the residues. The report of the Ministry of the Environment also confirmed "that in all the plants investigated, the use (of the residues) was expressly agreed to", said Faenger-Montag.

Meanwhile, the residues, which in turn were produced in the power plants that burned the Shell residues, could have been reused. According to the answer, such residues would partly be used as waste or by-product in the building materials industry.

SPD members of parliament Michael Hübner and Thomas Göddertz had criticised in their November petition that the residues had been falsely declared as regular fuel for years. Hübner said it was not sufficient to check only every three years whether emission values had been met.

(Original text: Katharina Weber; Translation: Mareike Graepel)