Is your vehicle's sunroof at risk of exploding?

Sunroofs are no longer just the province of luxury vehicles. These days, most car models have a sunroof option. Some even boast panoramic versions that span half the ceiling.

While it is indeed a luxury to enjoy the sunlight, views and fresh air, sunroofs have a downside: They could be ticking time bombs.

How it happens

A recent Consumer Reports investigation sheds light on the alarming "exploding sunroof" phenomenon. Drivers have reported hearing a deafening boom as their sunroofs shattered, resulting in a shower of broken glass. Typically, it happens without warning, and without any obvious cause.

These sudden blowups have affected a wide range of makes and models. The largest number of complaints, however, involve the Kia Optima, Kia Sorento, Scion tC, Nissan Murano and Hyundai Veloster.

Reports have skyrocketed with the increasing prevalence and popularity of sunroofs. The incidence rose from a scant three cases in 1995 to nearly two-hundred in 2014 alone.

What likely contributes

Because these "explosions" occur out of the blue, the likely culprits are defective glass and unsafe design.

As sunroofs have gotten bigger and bigger, so, too, has the number of reports. The Kia Sorento, for example, had zero incidents involving its earlier models. After a design change incorporated panoramic sunroofs, dozens of complaints surfaced. Large panes of glass are inherently weaker. What's more, panoramic sunroofs are often curved to fit the frame of the vehicle, further jeopardizing their structural integrity.

The type of glass may also play a role. Most automakers use tempered glass for sunroofs because it's cheap, light and thin. However, laminated and hybrid glass are stronger options. Tempered glass also tends to weaken more over time. The bumps and jolts of regular driving - along with exposure to changing temperatures - can make the entire pane vulnerable.

The potential for catastrophic consequences

So far, no serious injuries or deaths have occurred. But it's only a matter of time. Apart from the risk of injury from falling glass, such a startling and forceful blast could readily cause an accident.

Auto safety regulations haven't kept up with rapidly evolving sunroof designs. Glass standards, for example, haven't been updated since 1996. The National Highway Traffic Safety Administration is currently investigating the problem as it pertains to one specific model, the Kia Sorento. Yet auto makers themselves still have a responsibility to their customers - and the public at large - to improve the safety of their sunroofs before it's too late.