The UK’s Environment Agency is investigating three British waste disposal companies which allegedly sent more than 1,000 tonnes of falsely labelled recyclable waste to Poland.

The agency’s communications officer, Angus Anderson, said Polish inspectors discovered 45 containers of supposedly recyclable plastic filled instead with boxes, metal tins, detergent packaging, and engine oil.

As reported by the Organised Crime and Corruption Reporting Project (OCCRP) website, the inspectors suspect that the containers were intended for a group the Polish government calls a “trash mafia” after more than 60 fires flared up in landfills throughout Poland in May. The most famous one lasted more than two days and covered the town of Zgierz in smoke.

The trash burning is linked to a recent influx of waste into Poland blamed mostly on a ban China clamped on imported waste in March.

Radio Poland online noted that the UK annually sends to Poland 12,000 tonnes of recyclable plastic. But instead of recycling it, the plastic is being set alight and Poland’s “trash mafia” has been making millions of zloty in the process.

According to a report published by The Telegraph, the sudden rise of the trash mafia in Poland was fuelled partly by China’s recent ban on waste imports. Landfill owners paid millions for plastic waste, much of which subsequently went up in flames in mysterious circumstances, causing both the release of hazardous pollutants into the atmosphere and a huge expense for the nation’s emergency services tasked with putting out the fires.

In June, Poland’s Prime Minister Mateusz Morawiecki vowed to tackle the issue of landfill fires, submitting a bill to parliament intended to impose stricter restrictions on waste disposal.