TOKYO—Air bag maker Takata Corp. lost a quarter of its value in a single day Thursday, as more Japanese auto makers followed Honda Motor Co.'s footsteps and signaled they may also avoid using certain air-bag inflaters made by Takata in their new vehicles.

Mazda Motor Corp. said it won't use Takata-made air bag inflaters with ammonium-nitrate based propellant in vehicles currently under development. Fuji Heavy Industries, the maker of Subaru cars, said it is considering not using Takata's inflaters for new models, while Mitsubishi Motors said it is considering whether to switch to other suppliers in its new models.

The flurry of announcements came after Honda said earlier this week it will no longer use Takata-made front driver or passenger air-bag inflaters in new vehicles under development, alleging the supplier misrepresented and manipulated test data.

On Thursday, Takata shares plunged 25% to ¥ 889, the lowest level in more than six years. The company supplied tens of millions of explosive air bags that are being recalled world-wide. Takata is set to announce its second-quarter results Friday.

The move by auto makers underscores how they increasingly don't deem Takata inflaters necessary in future vehicles, raising questions about the viability of its inflater manufacturing operations in the long-run.

An inflater is a component inside an air bag module. Inside its metal casing are propellant tablets or wafers, which burn and emit gas to fill the air bag. Some of the air bags that Takata makes contain inflaters also made by Takata, while others contain inflaters made by non-Takata suppliers such as Daicel Corp.

The air bags under recall contain Takata-made inflaters that are at risk of exploding and shooting shrapnel, a problem linked to eight deaths.

Other inflater makers including Daicel and Autoliv Inc. have been or are considering ramping up production capacity to help Takata manufacture replacement air bags for recalled vehicles.

Such suppliers would be able to supply inflaters for new vehicles, because they will have extra capacity after they finish producing replacement parts for recalled vehicles, said Yasuyuki Yoshinaga, CEO of Fuji Heavy Industries.

"If suppliers invest in equipment and plants and if auto makers are going to continue buying components, then there would be no problem," he said.

Shares in Daicel rose 7.2% Thursday.

But for the time being, auto makers still need Takata to continue making replacement inflaters for many of the 19 million vehicles in the U.S., and millions elsewhere in the world, that have yet to be fixed. For certain types of air bag modules, other suppliers cannot easily offer a matching type of inflater due to differences in shapes, auto makers and officials said.

Takata also makes other automotive safety devices such as seat belts and child seats.

Takata spokesman Hideyuki Matsumoto said he can't comment on moves by Mazda, Subaru and Mitsubishi Motors because Takata hasn't communicated directly with those auto makers on the matter. "Our priority is to supply replacement parts quickly and to assure the safety of consumers," he said. "We want to do our best to win back the trust of auto makers for future inflaters."

The rejections of Takata-made inflaters come after U.S. auto-safety regulators ordered Takata this week to eventually stop using ammonium-nitrate based propellant in the safety devices.

One exception was Toyota Motor Corp., which kept its stance vague. "We will use inflaters that are safer and more reliable," Senior Managing Officer Shigeru Hayakawa said during an earnings briefing. He declined to comment in detail, saying the cause of the inflater explosions has yet to the identified.

Write to Yoko Kubota at yoko.kubota@wsj.com

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(END) Dow Jones Newswires

November 05, 2015 08:55 ET (13:55 GMT)