Graco has added more than 403,000 child car seats to last month's recall after issues with the harness buckles that made it difficult for parents to get their children out.

In February, Graco recalled around 3.7 million child car seats; however, the National Highway Traffic Safety Administration is still urging for an additional 1.8 million infant seats to be recalled, The Associated Press reported.

The more than 403,222 models that were recalled this week include 2006 through 2014 Argos 70 Elite, Ready Ride, Step 2, My Ride 65 with Safety Surround, My Size 70, Head Wise 70 with Safety Surround, Nautilus 3-in-1, Nautilus Plus, and Smart Seat with Safety Surround, the AP reported.

The car seat recall is the fourth-largest of its kind, but if the infant seats are recalled as well, it will be the biggest of all time.

Graco said in a letter to the NHTSA that the infant seats weren't included in the recall because they are employed differently than the child seats. The infant seats can be entirely removed from the car in case of an emergency, while child seats must be unlatched.

The harness issues generally happened when food and beverages consumed in the car seat made the harness sticky over time, so Graco has issued cleaning tips for the buckles. Some consumers have reportedly had to go to the extreme of cutting the seat's straps to get their child out.

No injuries have been reported in association with the issue. The 11 child car seat models recalled in February were the Cozy Cline, Comfort Sport, Classic Ride 50, My Ride 65, My Ride 65 with Safety Surround, My Ride 70, Size4Me 70, My Size 70, Head Wise 70 and Smart Seat.

The Atlanta-based company has been offering "new and improved replacement harness buckle to affected customers at no cost." To get a new buckle, call 800-345-4109 or email consumerservices@gracobaby.com.

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