Two U.S. senators are calling for Takata Corp. to voluntarily recall all of its air bags and to publicly release all company air bag test results so that independent experts can review them.

The senators, Richard Blumenthal (D-Conn.) and Edward J. Markey (D-Mass.), publicly released an Aug. 20 letter they sent to Takata. The letter expresses concerns arising from new reports of a June 7 explosion of a Takata side air bag in a 2015 Volkswagen Tiguan near St. Louis, Mo.

This incident “directly undercuts Takata’s continued insistence – despite growing evidence to the contrary – that the flaws in its airbag inflators are limited to prior designs in older model cars and only present when the airbags have prolonged exposure to extremely humid conditions,” the letter states.

The two senators are members of the Senate committee on commerce, science and transportation, which has held hearings on the Takata air bag recalls.

The National Highway Traffic Safety Administration is currently investigating the June 17 incident.

“As new reports surface of explosions in the latest models of Takata airbags, we write to express our deep concern over the obfuscation and delay that your company has engaged in while searching for a root cause of these defects,” the letter says. “Takata’s defective airbags have already caused at least eight deaths and more than one-hundred injuries in the United States – numbers that may increase as further cases come to light – and it is essential for your company to do all it can to identify and address the cause of this problem.”

The letter points out that the 2015 Volkswagen Tiguan wasn’t included in previous Takata air bag recalls, and also questions why Takata has continued to use ammonium nitrate mixtures in some of its new inflator designs.

In the letter, the senators express dismay at “Takata’s unwillingness to acknowledge the strong association between ammonium nitrate and the safety defect that has led to the rupturing of so many inflators.”

Blumenthal and Markey also criticize Takata for failing to establish a victim’s compensation fund. The letter is addressed to Kevin Kennedy, TK Holdings executive vice president for North America. TK Holdings, based in Michigan, operates as a subsidiary of Takata Corp. in Japan.

To ensure Takata’s replacement air bags are truly safe, the company needs to disclose all relevant test results involving new and previous inflator designs, the senators argue. The letter sets a Sept. 3 deadline for a Takata response. The company has thus far declined multiple media requests for comment on the letter.

To download a copy of the letter, click here.