A former medical officer for the National Transportation Safety Board told Forbes that he was shocked by the level of amphetamines listed last week in the autopsy of former Phillies pitcher Roy Halladay.

"I saw that number," Dr. Michael Garber told Forbes of the level of amphetamines in Halladay's cardiac blood, which was 1,800  nanograms per milliliter. "And said, 'Am I reading that right? 1800, holy cow.' That just jumps off the page at me."

The autopsy by the Pinellas-Pasco (Fla.) Medical Examiner's Office listed Halladay's cause of death as blunt force trauma with drowning as a contributing factor after his single-engine plane slammed into the Gulf of Mexico in November. The autopsy also found morphine and Ambien in Halladay's blood.

According to Forbes, amphetamines can cause death at 500 ng/ml and an overdose can could lead to reckless piloting of an airplane or debilitate the pilot with convulsions, hallucinations, restlessness and cardiac arrest.

"Assuming the toxicology report is accurate, the level of amphetamine in his blood is consistent with either an overdose or amphetamine addiction,"  Garber told Forbes. "He's exhibiting wild behaviors that could be the result of amphetamines in his system."

Garber is a senior managing consultant for ESi, an engineering and scientific investigation and analysis firm. He specializes in medical issues  in transportation and other accidents. According to the company's website, Garber participated in more than 1,000 transportation investigations with the NTSB.