Bomb squad removes cache of Civil War era cannonballs

While digging at a construction site in Lawrenceville, a Franjo Construction crew unearthed a familiar finding: a cache of Civil War cannonballs.

On July 2, a construction crew was turning soil for a new condominium development by Milhaus Ventures on 39th Street between the Allegheny River and Butler Street when they “struck something solid,” according to city police. When the excavator operator at the site realized what his machinery hit, he “promptly” called the city’s bomb squad.

“This was the same employee who had helped unearth 715 cannonballs while working not far from here in March of 2017, the site of the former Allegheny Arsenal, an important supply and manufacturing center for the Union Army during the American Civil War,” police said in a Facebook post.

City police spokeswoman Cara Cruz said the announcement was made over a month after the original discovery to keep the area secure and to keep people safe while police recovered the cannonballs.

“The process of securing the area and carefully excavating all of the cannonballs has been ongoing since that date in two locations in the general area,” Ms. Cruz said in an email. “... There is no map pinpointing where the cannonballs were placed, so the removal process has been deliberately thorough, which takes time.”

Ms. Cruz also said some cannonballs have already undergone mitigation, while others are still in the process.

The discovery is not unusual for the area, located at the site of the U.S. Allegheny Arsenal. The arsenal, which produced 128,000 rifle cartridges a day for Union troops during the Civil War, stretched from Penn Avenue to the Allegheny River.

In 1862, 78 people were killed when three explosions erupted in a building called the laboratory. It was one of the worst civilian disasters during the Civil War.

Police say they have yet to determine the exact number of cannonballs found in July. According to Pittsburgh police, the cannonballs are still live — and thus sensitive to shock, heat, friction and impact. The bomb squad unit will coordinate with the U.S. Army to handle the mitigation of the cannonballs, which are owned by the Army.