Albanian officials say they are investigating how 800 tons of alleged hazardous industrial waste was shipped from one of their ports without authorization, bound for Southeast Asia, as the suspect cargo is due to be sent back. 

Meanwhile, an A.P. Moller-Maersk A/S vessel transporting some of the suspect cargo offloaded the containers in Singapore over the weekend, having initially sailed past the port before doubling back to dock in an unusual move. Some 40 containers that environmental groups allege carry toxic dust waste were set to be transferred August 19 onto an MSC Mediterranean Shipping Company SA vessel that will ferry them back to Europe, according to MSC’s marine cargo tracking website. 

Maersk said it’s working with Singaporean authorities and MSC to return the cargo to Albania. For now, the containers are set to arrive at Italy’s Gioia Tauro port in late September, according to the tracking data. 

Another 60 containers of suspected waste which is currently on board another Maersk container ship — due in Singapore later this month — will also head back to Europe, Maersk said. 

Singaporean officials said they are “facilitating the return of these containers” under the United Nations Basel Convention, a global pact signed by many developed economies that requires countries to give consent for waste headed their way. 

“We have received information concerning the carriage by two Maersk vessels of some containers that reportedly contain undeclared hazardous waste,” the National Environment Agency and the Maritime and Port Authority of Singapore said in a joint statement in response to a Bloomberg query. “We have informed Maersk, which has updated us that they will ship the containers back to the country of export.” 

Officials have been working to stop the shipment since Basel Action Network, a U.S.-based nonprofit that tracks toxic trade, informed Thailand earlier this month that the containers it believes are filled with potentially harmful electric arc furnace dust were heading to its port.

Bloomberg News couldn’t independently verify what the ships are carrying. The companies exporting and receiving the containers haven’t been identified. MSC didn’t respond to requests for comment. Maersk said none of the containers were declared to contain hazardous waste, otherwise it would have declined to carry them.

Environmentalists have been working to thwart the influx of trash from developed countries to Thailand and other Southeast Asian countries — from dirty plastic to industrial and electronic waste that are often laced with toxins.

The journey of the suspect containers has set off alarms in multiple countries since they were loaded at the Albanian port of Durres in July, with a final destination of Thailand scheduled for later this month. Thailand refused to accept the shipment after being alerted of its alleged hazardous contents by environmental groups.

As the ships neared Cape Town, South African officials tracked the vessels and put a plan in place that included the navy, police, port authorities and the environment department to conduct a full inspection when the ships docked, said a spokesman for the Department of Forestry, Fisheries and the Environment. After communication with Maersk, the company told South Africa the ships weren’t scheduled to dock there and would continue on their way to Singapore. 

Albania’s Ministry of Tourism and Environment hadn’t given authorization for the export of the alleged hazardous waste, according to spokesman Erjon Uka. Albanian law enforcement are carrying out investigations with the European Union Anti-Fraud Office on “the circumstances and all the logistical links that have carried out this suspected transport from Europe to Southeast Asia,” he said.  

The waste is suspected to come from international companies operating near a metallurgical complex in Elbasan, near Durres, he said. 

The furnace dust, which requires treatment, is a hazardous waste product that commonly comes from recycling scrap steel and contains toxic metal oxides like cadmium and chromium that are harmful to health and the environment. 

“International conventions, and domestic legislation consistent with them, provide a series of obligations for producers and transporters of such waste,” Uka said. “The implementation of these obligations is also the subject of ongoing investigations.”