Not everyone is aware that infant and child safety seats actually have expiration dates. In fact, many are bought and sold at garage or yard sales even though they have passed their expiration date. A child or infant safety seat is considered expired five to six years after production (not purchase). The plastics used in making them can deteriorate due to exposure to sun and heat, rendering the seats unsafe. Some communities have designated spots for dropping off expired car seats, along with some specifics about how they will receive them.
The most important thing to note when disposing of an expired car seat is that they almost never look like they are in bad shape. In fact, some of expired car seats look like they're in wonderful condition; especially the ones that were fairly expensive to begin with. If an expired car seat is simply left sitting next to your trash can on garbage day, it is almost a guarantee that someone will come along and pick it up either for use or resale. To the average person, this car seat will appear like one a child has simply outgrown--and it will likely be passed on, one way or another, to an unsuspecting family.
If possible, it's wise to break the heavy plastic on the car seat's structure. Even sawing it in half is an option, if you can do it safely.
For the very same reason, disguising the discarded expired car seat is another viable option. Double-bag the seat in green trash bags and add additional trash to the bag so that the temptation to rummage through the bag is avoided. Taking it directly to the curb when the trash truck arrives and watching them throw the bag into the back of the truck will also alleviate any worries about the car seat making its way into someone else's car. If you have access to a dumpster, you can disguise the car seat in a similar fashion and dump it there--throwing additional bags of garbage over it.
Some communities have drop-off sites for expired car seats, and businesses occasionally will do this as a community service. If you cannot find such a drop-off location in your community, calling your local police or fire department should produce an address for a nearby drop-off location for your expired car seat.
Some of these programs will require that the expired car seat be in some form of disassembly, so it's always best to call ahead for specifics before dropping one off.
Do a Good Deed
Some communities now offer certain programs that allow these expired car seats to be recycled. This doesn't mean they are recycled as in reused, but simply means they will be taken apart and disposed of in a way that will not harm the environment.
As with drop-off programs, some recycling programs will require some disassembly, so check with them before recycling the expired car seat.