Smart Colorado, a group that advocates against youth marijuana consumption, announced on Monday that it will mail signs to all 774 marijuana retail stores in the state that warn pregnant and breastfeeding mothers about the risks the drug poses to them.

“We determined that the state was not providing signage to help Colorado’s marijuana businesses comply with the new law requiring the warning signs so we took the initiative to mail out signs at no cost to the dispensaries,” said Henny Lasley, the group’s executive director.

The Department of Revenue’s Marijuana Enforcement Division requires that starting in 2020, retailers post a sign at least three inches by six inches that reads: “Warning: Using marijuana, in any form, while you are pregnant or breastfeeding passes THC to your baby and may be harmful to your baby. There is no known safe amount of marijuana use during pregnancy or breastfeeding.”

Smart Colorado included a version of the sign with their letter to store owners, reminding them that the sign must be in a prominent location inside the restricted access area.

“We thank you for your efforts to protect our youngest members of society who deserve optimal brain development. They have just one chance to grow up,” Lasley wrote in the letter.