He landed on his head and neck.
The explosion caused a traumatic brain injury, but at the time, medical personnel thought it was a concussion that would resolve itself.
It did not. The brain injury eventually resulted in Johnson, 40, going blind.
On Saturday morning, nearly six years after the incident, theU.S. Armyawarded Johnson a Purple Heart Medal at a ceremony at the Army Reserve Center in Aberdeen.
Johnson, a member of the 452nd Ordnance Company Army Reserve, said he is not bitter about the long delay. He understands that Army medics were not looking for the signs of traumatic brain injury in 2006. The Army Traumatic Brain Injury Task Force wasn't chartered until 2007, and the recommendations for screening and treatment weren't released until Jan. 17, 2008.
He said he also realizes that the diagnosis was not easy because many of his symptoms — nausea, confusion, dizziness, fatigue — were also symptoms of salmonella poisoning, which he contracted after the brain injury.
The bestowal of the Purple Heart, however late, means a lot to him.
"It is an acknowledgement from the Army of the injuries that I have," he said. "After having to fight to get a diagnosis and care, it validates what we went through."
The debilitating affects of the injury unfolded over time. His wife, Melissa Johnson, said his memory and decision making grew worse after he returned home in 2007. He also began showing mood symptoms such as increased anger. His eyesight began to fail.
In addition to the brain injury, he suffered from Post Traumatic Stress Disorder with symptoms such as increased anxiety, nightmares and flashbacks.
Johnson, who has served in the Army for 23 years including deployments to the Persian Gulf War (1990-1991) and Bosnian conflict (1997), said his life changed after that mortar attack at Camp LSA Anaconda. ¿He was standing in the parking lot at 7 a.m. talking with a few other soldiers when a mortar shell landed about 100 yards away. The soldiers did not immediately react because mortar attacks were common at the base, he said.
"When we first arrived we were in the bunkers 5-6 times a day," he said. "By March, we were in the bunkers 1-2 times a day."
Several shells followed in succession. It was the third motor round that landed close to him.
"All I remember was a bright, white light," he said. "I was blown backwards and landed on the back of my neck."
He was dazed and disoriented, but remained conscience.
He lost his hearing for the next 24 hours.
"It was totally quiet," he said. "It was kind of scary."
He received medical attention, but after a short time, he was back on full duty.
"At that time, they looked you over, and if you weren't bleeding, you were OK," said Melissa Johnson.