WASHINGTON, D.C. — Graco Children’s Products has been fined $10 million after the company failed to provide timely notification of a defect in more than 4 million car seats, U.S. Transportation Secretary Anthony Foxx said on Friday.

Graco must pay a fine of $3 million immediately to the federal government, and an additional $7 million is due in five years unless the company spends at least the same amount on new steps to improve child safety.

The penalties close an investigation launched in December by the National Highway Traffic Safety Administration (NHTSA) into whether Graco failed its obligations, under the National Traffic and Motor Vehicle Safety Act, to begin what ended up as the largest-ever recall of child seats. The seats had buckles that could stick or become stuck in a latched position, potentially placing child occupants at risk in an emergency.

“Parents need to know that the seats they trust to protect their children are safe, and that when there’s a problem, the manufacturer will meet its obligations to fix the defect quickly,” Foxx said. “Today’s action reinforces that responsibility in a way that will make our kids safer for decades to come.”

Graco will create a plan and procedures for addressing certain targeted performance requirements. Those may include methods to increase effectiveness of consumer product registration of car seats, which allows parents to be notified of defects; identifying potential safety trends affecting car seats industry-wide; and launching a child safety awareness campaign.

According to NHTSA, on average, only 40% of people who have recalled car seats get them fixed. That’s in comparison to an average of 75% of people who have recalled light vehicles, for which registration is required by law.

The National Traffic and Motor Vehicle Safety Act states that once a manufacturer knows or should reasonably know that an item of motor vehicle equipment, such as a car seat, contains a safety-related defect, the manufacturer has a maximum of five business days to notify NHTSA. Once the manufacturer notifies the agency of a defect, it is required to launch a recall.

Under a consent order issued on Friday, Graco admits that it did not provide the required defect notice. Under pressure from NHTSA, Graco recalled more than 4 million convertible and booster seats with defective buckles in February 2014, and nearly an additional 2 million rear-facing infant seats in June.

To read the consent order with Graco, click here. For more information about registering car seats to receive recall notifications, go here.