US safety regulators are demanding that General Motors turn over documents detailing what the company knew, and when, about a dangerous ignition problem that has been linked to 13 car-crash deaths.

The National Highway Traffic Safety Administration is investigating how GM handled the problem, which triggered the recall of 1.6 million older-model compact cars worldwide. GM has acknowledged it knew of ignition troubles a decade ago but didn’t recall the cars until last month.

GM received an order seeking the information yesterday, company spokesman Alan Adler said. In a statement issued today, Adler said the company is cooperating and welcomes the chance to help NHTSA fully understand the facts.

GM has until April 3 to produce the documents. In similar cases, such as the Toyota unintended acceleration recalls, NHTSA has demanded large volumes of information.

NHTSA wants the documents to determine if GM delayed its response or withheld evidence. If either case, NHTSA could fine GM up to $35 million. Automakers are required to inform NHTSA of safety defects within five days of discovering them.

Such a fine would be a record for NHTSA, but essentially is pocket change for GM, which made $3.8 billion last year.

Still, the facts surrounding the recall are embarrassing for GM and could scare away consumers. Since undergoing a painful bankruptcy in 2009, GM has removed layers of bureaucracy, improved the quality of its vehicles and is quicker to issue recalls when problems occur. However, the admission that its procedures were lacking 10 years ago shows how the old culture can still haunt the automaker.

In an effort to reassure employees and customers, GM’s new CEO Mary Barra yesterday promised an “unvarnished” internal investigation to figure out what happened and prevent it from recurring.

“We want our customers to know that today’s GM is committed to fixing this problem in a manner that earns their trust,” GM’s Adler said.

The maximum fine NHTSA can charge was more than doubled last year under legislation approved by Congress after the Toyota recalls. But critics say it still isn’t enough to deter bad behaviour by automakers.