The bombings in Boston will have a ripple effect on security at races across the country, said the chief running officer for Lehigh County-based "Runner's World" magazine.
Bart Yasso returned home from Boston on Tuesday and was still in shock.
"I knew what it was because I've heard that noise and smell, said Yasso. "Smelled that smell before and knowing that noise. I knew it was a bomb."
Yasso has traveled all over the world, covering running events and teaching. This is the third time he's been a witness to a bombing.
The first time came while he was a guest of the U.S. Department of Defense in Iraq, setting up 5K races for soldiers.
"All these people with guns. They say don't move," added Yasso. "Four in the morning, we heard this motor shell hit a building close to where I was housed. It was a loud noise."
The second time came two years later at the Jerusalem Marathon.
"That I don't think was targeted for the race," said Yasso. "I just think it happened just the day before the race and close to the race headquarters. It was kind of one of those things that is just more commonplace in a place like Jerusalem."
Yasso helps with the Runner's World marathon in Bethlehem and other marathons across the country. He said what happened in Boston will change security at all marathons.
"Making areas more secure where large gatherings of people end up, so there tends to be a lot of people at the start line, finish line," said Yasso, admitting that it will be tough to protect the 26.2 mile course.