Lego Group unveiled a prototype building block from sustainable materials as part of the toymaker’s plans to wean itself off oil-based plastic.

Lego said it used recycled plastic from discarded bottles, after testing more than 250 variations of sustainable plastic material over three years. On average, a 1-liter plastic polyethylene terephthalate bottle provides enough raw material for 10 standard-sized bricks, the Danish company said Wednesday.

Working to create a sustainable Lego brick from Alabama NewsCenter on Vimeo.

Lego has so far set aside about $400 million to go green and is working on finding sustainable materials for the almost 100,000 tons of plastic bricks it produces each year. It has some 150 employees working on sustainable projects.

Finding recycled material that meets quality and safety requirements has been difficult, Lego said. The prototype meets those demands as well as so-called “clutch power,” a key ability for the building bricks.

Still, the company said it “will be some time” before bricks made from recycled material appear in product boxes, because tests of the product need to continue for at least a year.

“Even though it will be a while before they will be able to play with bricks made from recycled plastic, we want to let kids know we’re working on it,” said Tim Brooks, head of environmental responsibility.