Lego has stopped a project to make bricks from recycled drinks bottles instead of oil-based plastic, saying it would have led to higher carbon emissions over the product’s lifetime, according to The Guardian.

The move followed efforts by the world’s largest toy-maker to use more sustainable materials, as part of a widespread trend of companies attempting to reduce their contribution to global emissions.

The Danish company makes billions of Lego pieces a year, and in 2021 began researching a potential transition to recycled polyethylene terephthalate (PET) from acrylonitrile butadiene styrene (ABS), which needs about 2kg (4.4lbs) of petroleum to make 1kg of plastic. ABS is used in about 80% of Lego blocks.

The “level of disruption to the manufacturing environment was such that we needed to change everything in our factories” to scale up recycled PET use, said Tim Brooks, Lego’s head of sustainability. “After all that, the carbon footprint would have been higher. It was disappointing.”

The company said in 2021 it had more than 150 people working on sustainability. But Lego’s chief executive, Niels Christiansen, told the Financial Times the toy-maker “tested hundreds and hundreds of materials” but could not find a “magic material” to solve sustainability issues.