A crew member shows the dig site where the cannonballs were discovered on March 27th.

A construction crew working in Lawrenceville discovered a cache of buried cannonballs today at the site of an old civil war arsenal, according to Pittsburgh police.

The construction crew building apartments across the street from Arsenal Middle School near 39th and Butler streets discovered between 35 and 43 cannonballs, a company spokesman said.

Police spokeswoman Sonya Toler said the police bureau's bomb squad responded to the scene but decided to allow the construction company's subcontractor, Ordnance Holdings Inc. in Maryland, to remove the cannonballs.

“They are specially trained for this type of work,” she said. “These cannonballs are stable when left alone.”

Still, police are posting an officer at the site to ensure no one disturbs the cannonballs, she said.

The subcontractor should be on site to remove the cannonballs within 24 hours.

The Allegheny Arsenal was a key supplier of munitions to the Union Army during the Civil War and was the site of the single worst civilian disaster of the war when an explosion killed 78 people, many of them women.

Pittsburgh also manufactured the largest cannons ever made — at the Fort Pitt Foundry, located in the Strip District during the Civil War.

For more information, visit www.post-gazette.com

Today's top stories

VIDEO: $4.7B Gordie Howe International Bridge Project Nears Completion

Volvo CE Upgrades Straight Boom Demolition Excavators

Construction Market Boosts Economy

Bobcat Company Donates $885,000 in Equipment to Support Salvation Army's Disaster Relief Efforts

VIDEO: KEMROC Expands; Plans to Increase Nationwide Presence

INFRA Grant Moves Ohio's N. Coast Connector Project Steps Closer

John Deere Construction Introduces Flexible Customer Training Options

VIDEO: First of Two Sections of NYC's $1.45B East Side Coastal Resiliency Project Is Complete