Lego has ditched plans to make bricks out of recycled drinks bottles after finding the new material failed to cut carbon emissions.

The Danish toy giant announced in 2021 it was researching whether PET plastic, or polyethylene terephthalate – which does not degrade in quality when recycled – could be used to make its building bricks.

It was part of a plan to shift to oil-free bricks, with Lego hoping recycled PET plastic could replace crude oil-based acrylonitrile butadiene styrene (ABS), which is currently used in pieces.

But the firm said that after more than two years of testing, it found the new material did not reduce carbon emissions.

Lego stressed it remains “fully committed” to making its bricks from sustainable materials by 2032 despite the setback.

It said it was still testing a range of alternative sustainable materials to use in making bricks, including other recycled plastics, as well as plastics made from other sources, such as e-methanol.

A Lego spokesman said: “We remain fully committed to making Lego bricks from sustainable materials by 2032.

“We are investing more than 1.4 billion US dollars (£1.1 billion) in sustainability initiatives in the four years to 2025 as part of our efforts to transition to more sustainable materials and reduce our carbon emissions by 37% by 2032.”

The group has been making a push to boost its sustainable credentials in recent years, with aims to find an alternative to oil-based plastic bricks, as well as rolling out paper-based packaging as part of aims to stop using plastic bags by the end of 2025.

Lego’s chief executive Niels Christiansen told the Financial Times newspaper, which first reported the firm’s move to scrap the PET bricks project, there was no “magic material” to solve sustainability issues.

He said: “We tested hundreds and hundreds of materials. It’s just not been possible to find a material like that.”

The firm also said PET plastic would cause higher carbon emissions over the product’s lifetime as it required new equipment, according to the FT.

Tim Brooks, the Lego Group’s head of sustainability, told the FT that PET plastic needed extra ingredients to give it safety and durability, as well as large quantities of energy to process and dry it.

“It’s like trying to make a bike out of wood rather than steel,” he said.