The toy company Lego is under fire from environmental group Greenpeace for a line of toy cars that feature Shell oil company. Greenpeace has collected over 750,000 signatures on a petition asking Lego to dissolve ties to Shell because of their destructive drilling in the melting Arctic.

The cross-promotion is a lucrative PR move for Shell, with Lego featuring a line of toy cars branded with bright Shell logos. Greenpeace is protesting the partnership, saying that Lego is boosting Shell's image and exploiting children in the process.

"Everyone loves to play with Legos, but no one wants to see you play with Shell," Greenpeace's public message to Lego says, which petitioners can send to the toy manufacturer.

The open letter to Lego goes on to say that it is "disappointing" that the toys feature Shell and urges Lego to break ties.

"With three quarters of the ice gone, it's time to hear the alarm clock ring and put an immediate halt to climate change," the message reads. "The oil companies with Shell in the foreground are not listening. Instead, they see opportunities to exploit this vulnerable and pristine place and drill for more of the oil that caused the problem in the first place."

The toy brand was founded in the 1930s by Ole Kirk Christiansen on the ideas of creative play and healthy child development. The name of the company even translates to "play well."

The environmental campaign asks Lego to stop all Shell promotions and raise awareness about the Arctic. The partnership raises questions about the ethics of advertising to kids. In places like Quebec, Sweden and Norway, advertising to children under 12 years of age is illegal, but elsewhere, kids are overloaded with messages for everything from food and drink to brands of gasoline like Shell.