Those LEGO bricks you played with as a kid (and perhaps still do, no judgment here) could end up in the ocean for over 1,000 years, but the Danish brickmakers are looking to dramatically build the eco-friendly credentials of their company. In its latest pledge, LEGO will start replacing plastic bags with paper bags from 2021 after being prompted by letters from children asking it to ditch the single-use plastic bags.

The promise comes as part of LEGO's recent announcement that it is investing $400 million over three years to improve its sustainability efforts. Among its many pledges, the company is looking to make all of its bricks out of sustainable materials by 2030, all packaging sustainable by the end of 2025, and all manufacturing operations carbon neutral by the end of 2022. 

“We have received many letters from children about the environment asking us to remove single-use plastic packaging. We have been exploring alternatives for some time and the passion and ideas from children inspired us to begin to make the change,” Niels B Christiansen, CEO of LEGO Group, said in a statement. 

“We cannot lose sight of the fundamental challenges facing future generations. It’s critical we take urgent action now to care for the planet and future generations.” 

It is estimated that around 440 billion LEGO parts and pieces have been manufactured since the company started production in 1949 — and they’re not going away anytime soon. A study earlier this year, published in the journal Environmental Pollution, estimated that the plastic bricks might linger in the environment anywhere from 100 to 1,300 years. On top of the bricks, there is also the concern of non-biodegradable plastic packaging that’s often used with the products.

Around 80 percent of LEGO pieces are made of a petroleum-based substance known as acrylonitrile-butadiene-styrene or ABS. Unfortunately, it’s a real challenge to find a non-biodegradable alternative to this material that's still sturdy, safe, and easy on the eye. LEGO is currently looking at the idea of switching the majority of their bricks to sugarcane-based polyethylene rather than oil-based plastic, but some challenges remain. To ensure the new bricks and pieces are both safe and practical, LEGO has a Sustainable Materials Programme that involves over 150 experts working on making their products and packaging more sustainable.

"At a time when the world is facing numerous challenges, companies must take action to create a lasting positive impact on the environment and society," added Christiansen. "No one can do it alone. I urge companies, governments, parents, children, and NGOs to continue to join forces to create a sustainable future for our children, the builders of tomorrow."