By Patrick Rucker and Ben Klayman
WASHINGTON/DETROIT (Reuters) - Japanese auto parts supplier Takata Corp on Wednesday acknowledged that it still does not understand what is causing air bag explosions that have hurtled metal shards into vehicles even as it insisted that calls for a broader recall to remedy the problem were misguided.
Takata is under pressure from U.S. lawmakers and safety regulators to expand to all 50 states a recall of driver-side air bags, but the company has said data does not support such a move and it could divert replacement parts from the most-needed areas.
So far, Takata and automakers have largely focused recalls on regions with high humidity believed to make aging air bag propellants more volatile.
?Congressman, we don?t identify the root cause yet," Hiroshi Shimizu, a Takata safety executive who gave his testimony with help from an interpreter told Representative John Sarbanes. "But we are of the strong opinion that (there) is a factor contributing to this defect: which is high humidity, temperature and the life of the product.?
The exchange came at a House Energy and Commerce subcommittee hearing on the Takata air bag problems which took place a day after Takata told the National Highway Traffic Safety Administration on Tuesday that current data does not support the need for such an expanded recall.
Still the stance of Takata, which is at the center of a global safety scandal that has involved the recall of more than 16 million cars worldwide and been linked to at least five fatalities, may be increasingly at odds with its customers.
A Honda Motor Co executive said on Wednesday that the automaker will expand the driver-side air bag recall to a national campaign, but added priority for the replacement parts should still be given to regions with higher humidity.
Takata also said it was surprised by the agency's request because a defect investigation has not been concluded.
The NHTSA late on Tuesday called the Japanese parts maker's response "disappointing," a sentiment echoed by lawmakers during Wednesday's hearing.
It remains unclear how quickly U.S. safety regulators can compel Takata to take the recall nationwide if it continues to resist. NHTSA officials said on Wednesday that it could likely take many months before the feds can move to compel such a recall.
However, Takata, whose air bags supply roughly a fifth of all cars on the road, and automakers who are its customers have struggled to pinpoint the exact cause of the defect.
Humid weather may provoke a dangerous air bag discharge, Shimizu said, explaining the company's rational for endorsing a recall in Puerto Rico, the Virgin Islands and Florida.
But lawmakers were skeptical and said the company was using arbitrary lines to set the scope for its recall effort.
"Does that make sense to you?" Rep. Henry Waxman asked the executives of a recall campaign that would warn Florida drivers about air bag dangers but not consumers in neighboring Georgia.
"If you are in Florida, just below the line, you have to go in and get a replacement??
Takata has said it makes sense to direct a limited supply of replacement parts to regions with a higher perceived risk.
Lawmakers said the supplier's answers were unsatisfactory and gave the public little confidence that it has a handle on the scope of the safety crisis.
"Complexity is not an excuse for incompetence," said Republican Representative Fred Upton of Michigan. "What should I say to the mom in Michigan who asks me if she and her family are safe behind the wheel?"
(Additional reporting by Eric Beech in Washington and Bernie Woodall in Detroit; editing by Matthew Lewis)
