The Takata airbag inflator recall has reared its head again with the news GM will recall 7m vehicles worldwide.

According to Reuters, the National Highway Traffic Safety Administration (NHTSA) rejected the automaker's petition to avoid the callback and said GM must recall 5.9m 2007-2014 model year trucks and SUVs in the US because the inflators "are at risk of the same type of explosion after long-term exposure to high heat and humidity as other recalled Takata inflators".

Reuters said GM had estimated in securities filings it would cost US$1.2bn if it were required to replace air bag inflators it had sought to avoid fixing and the company confirmed the estimated cost on Monday. It will recall 7m vehicles worldwide, including 544,000 in Canada.

The company had argued the recalls were unnecessary because the inflators did not pose a safety risk.

GM said in a statement: "Although we believe a recall of these vehicles is not warranted based on the factual and scientific record, NHTSA has directed that we replace the airbag inflators in the vehicles in question. Based on data generated through independent scientific evaluation conducted over several years, we disagree with NHTSA's position. However, we will abide by NHTSA's decision and begin taking the necessary steps."

Reuters said the defect, which leads in rare instances to air bag inflators rupturing and sending potentially deadly metal fragments flying, especially after long term exposure to high humidity, prompted the largest automotive recall in US history of more than 63m inflators. Worldwide, about 100m inflators by 19 major automakers have been recalled.

The latest recall includes some Cadillac Escalade, Chevrolet Silverado, Chevrolet Suburban, Chevrolet Tahoe, GMC Sierra and GMC Yukon vehicles built over an eight year period.

Reuters said GM first filed a petition in 2016 seeking to avoid the recall. NHTSA noted that in nearly 30 years, it had only granted one petition deeming a "defect is inconsequential to motor vehicle safety" and "in a vastly different set of circumstances".

GM argued the 5.9m vehicles were different from other vehicles with Takata inflators. The automaker estimated 66,894 Takata passenger air bag inflators have deployed in the vehicles under review without a reported rupture.

Peter Prieto, a lawyer representing consumers in Takata lawsuits, told Reuters the decision "proves that GM's Takata inflators are neither unique nor special. GM's inflators carry the same risk of exploding and severely harming vehicle occupants as all other Takata inflators".