Whistle-blowers have told the Senate Commerce Committee that safety inspectors at the Federal Aviation Administration, including those involved with approvals for the Boeing Co. 737 Max, lacked proper training and certifications, according to the panel's chairman.

"Multiple whistleblowers" provided the committee with information alleging that "numerous FAA employees, including those involved in the Aircraft Evaluation Group for the Boeing 737 MAX, had not received proper training and valid certifications," Sen. Roger Wicker, a Mississippi Republican, said in a letter to the FAA Acting Administrator Daniel Elwell Tuesday.

Those claims and two 737 Max crashes since October that have killed 346 people prompted Wicker to launch an investigation into potential connections between training and certification shortcomings and the FAA's evaluation of the airliner, he said in his letter, which was released by the committee Tuesday.