Modern airbags are designed to last the entire lifespan of the vehicle and do not have a set expiration date. This wasn’t always the case. Older vehicles, particularly those made in the early-to-mid 1990s, often came with owner’s manuals recommending airbag inspections every 10 years. Today’s airbag systems use more stable chemical propellants, and manufacturers no longer include routine replacement schedules. That said, several real-world factors can shorten an airbag’s functional life, and the massive Takata recall showed just how badly things can go wrong.
Why Older Vehicles Had Expiration Windows
Early airbag systems relied on sodium azide as the propellant. When triggered by a crash sensor, the sodium azide ignited and rapidly produced nitrogen gas to inflate the bag. The chemistry worked, but it came with complications. The reaction also produced sodium metal, which could react with moisture in the air to form corrosive sodium hydroxide. Manufacturers added potassium nitrate and silicon dioxide to neutralize the sodium, but over many years the seals protecting these chemicals could degrade.
Honda and Acura, for example, recommended dealer inspections of airbag systems every 10 years in their early-to-late 1990s models. The concern was that a decade of temperature swings and humidity exposure could compromise the inflator’s integrity. If you’re driving a vehicle from that era that still has its original airbags, there’s no built-in self-test that can tell you whether the propellant inside has degraded.
What Changed in Modern Airbags
Today’s airbag inflators use guanidinium nitrate paired with a copper nitrate oxidizer. When ignited, the guanidinium nitrate breaks down into nitrogen gas, water, and carbon. The copper nitrate helps lower the temperature of the exhaust gas, making the entire deployment more controlled. This chemistry is significantly more stable over time than the older sodium azide systems, which is why current manufacturers say airbags will last the life of the car without needing replacement, as long as they haven’t deployed in a crash.
The Takata Recall: A Cautionary Example
The largest auto recall in U.S. history involved Takata airbag inflators that used ammonium nitrate as a propellant. Over time, exposure to heat and humidity caused the ammonium nitrate to break down. When these degraded airbags deployed, hot gas blew through the inflator’s internal structure in 3 to 5 milliseconds instead of the intended 30 milliseconds. The result was an explosion that sent metal shrapnel into the vehicle cabin.
According to NHTSA, the risk was highest in vehicles that spent years in hot, humid climates. One airbag safety researcher estimated that in those regions, ammonium nitrate inflators could become compromised in as few as 6 years. Tens of millions of vehicles were recalled. If you’re unsure whether your vehicle is affected, you can check by entering your VIN at NHTSA.gov/recalls.
How Climate Affects Airbag Longevity
Heat and humidity are the two biggest environmental threats to airbag inflators, regardless of the propellant type. The propellant sits sealed inside a metal canister for years or decades without being used, and the seals protecting it are exposed to constant temperature cycling. In a car parked in direct sun in Florida or Texas, the interior temperature can swing dramatically every single day. Over 10 or 15 years, those cycles stress the seals and can allow moisture to reach the propellant.
If you live in a hot, humid climate and drive an older vehicle, the airbags carry more risk than the same system in a car that spent its life in a cool, dry region. Parking in a garage or shaded area helps, but it doesn’t eliminate the issue entirely.
The SRS Warning Light
Your vehicle’s supplemental restraint system (SRS) runs a self-diagnostic check every time you start the car. You’ll see the SRS or airbag warning light briefly illuminate on the dashboard, then turn off within a few seconds. That brief flash means the system checked itself and found no faults.
If the light stays on or blinks continuously, the airbag system has detected a problem and may not deploy in a crash. The causes range from minor issues, like a loose wiring connector under the seat, to serious ones like a failing airbag control module. Even a small corrosion spot on a connector pin can trigger the warning. Older systems are especially prone to lighting up over any wiring fault. A steady SRS light should be treated as urgent, since it means your airbags are potentially nonfunctional.
One thing the SRS system cannot do is test the chemical propellant inside the inflator. It checks electrical connections, sensors, and the control module, but the actual condition of the propellant and its seals is invisible to the diagnostic system.
Other Components That Age
The inflator gets the most attention, but the airbag system includes several other parts that can fail with age. The clock spring, a coiled ribbon cable inside the steering column, maintains the electrical connection to the driver’s airbag as you turn the wheel. When it wears out or breaks, the airbag loses its ability to deploy. Common signs of a failing clock spring include the SRS warning light turning on (especially while turning), a horn that stops working, and steering wheel buttons that become intermittent. Replacing a clock spring costs around $440 including parts and labor.
Crash sensors and the airbag control module can also degrade over time. A new impact sensor runs about $210 for the part plus around $100 for labor. Replacing the control module is more expensive, typically $700 to $840 total.
What Replacement Costs Look Like
If an airbag has deployed in a crash, replacing the full system typically costs between $1,500 and $6,000, depending on how many airbags fired and what other components were damaged. Replacing a single airbag module that hasn’t deployed but needs replacement for another reason costs around $750 total, with roughly $500 for the part and $250 for labor.
For older vehicles, the cost of airbag replacement can approach or exceed the car’s value. That’s worth factoring in if you’re keeping a 1990s vehicle on the road and wondering whether to invest in the airbag system or put that money toward a newer car with modern safety features.
Practical Takeaways for Your Vehicle
If your car was built in the 2000s or later and uses a modern propellant system, your airbags should last as long as the car does, assuming no crash deployment and no recall issues. Check your VIN against open recalls periodically, pay attention to the SRS warning light, and don’t ignore a horn that suddenly stops working, since it may signal a clock spring failure that also affects your airbag.
If you’re driving a vehicle from the 1990s or earlier, check the owner’s manual for any airbag service intervals. Even if no interval is listed, the inflator seals in a 25-plus-year-old car have endured decades of temperature cycling, and there’s no diagnostic that can confirm the propellant is still stable. Vehicles that have spent most of their lives in hot, humid regions carry the highest risk.