Tesla is voluntarily recalling the approximately 90,000 Model S sedans that are on the road worldwide. The affected vehicles have front seat belts that could fail to function correctly in an accident.

According to a representative at Tesla, a single Model S in Europe experienced a seat-belt malfunction.

There was no accident, but when an owner turned around to speak with passengers in the rear seat, her seat belt came loose. The owner notified Tesla, and the company confirmed the fault, which could cause the seat belt to tighten incorrectly in a crash. Tesla repaired the defective seat belt.

There have been no other incidents, and Tesla has inspected 3,000 Model S vehicles since early November, when the problem was first reported. The company explained that the potential flaw is related to a bolt that would take a few minutes to inspect and repair at a Tesla service center. The cost, according to Tesla, is "immaterial."

The company emphasized that while it has reported the incident to regulators globally, it has not yet been required to recall the affected vehicles. Instead, Tesla is recalling every Model S on the road out of an "abundance of caution," the Tesla representative said.

The problem affects only front seat belts, not rear. And the Model S is the only vehicle affected. The recently launched Model X SUV doesn't have the problem, which Tesla has concluded developed during the assembly process at the automaker's California factory, not with a parts supplier.

The Model X SUV isn't affected by the recall. Benjamin Zhang / BI

In an email to owners, Tesla said: "First and foremost, we care about your safety." And it outlined a process for owners to have their vehicles inspected. They can book an inspection online or visit a service center. Tesla also said that it's exploring ways to send technicians to owners who can't easily get to one of its 125 service centers, and that it may be able to perform an inspection at Supercharger stations.

Owners can also self-test their seat belts; but Tesla said that this isn't a substitute for an official inspection.

"If you are concerned about the status of your seat belt prior to your scheduled inspection, you may be able to detect this condition by pulling very firmly on the lap portion of your seat belt with a force of at least 80 pounds," the carmaker said in its email. "This procedure may detect an improperly attached seat belt but performing this procedure does not replace the need for an inspection by a Tesla technician."

This is largest recall in Tesla's history, but it comes at a time with massive safety-related recalls have roiled the industry. General Motors recalled millions of cars worldwide for an ignition-switch defect that could cause airbags to malfunction in a crash. And Takata has been involved in a massive global recall of vehicles by numerous manufacturers because of airbag inflators that can spray occupants with metal shards.

"This goes above and beyond what's traditional in the industry," the Tesla representative said. "But from [CEO] Elon Musk on down it was unacceptable to Tesla."

Tesla shares were trading down slightly in trading Monday, dipping to $214 before rebounding to around $220.