The planned demolition of a key portion of the collapsed Francis Scott Key Bridge is set to begin Monday after inclement weather, including lightning, forced the operation to be postponed over the weekend.

The demolition, which includes using small explosives to break apart a massive chunk of the Baltimore bridge that collapsed on a cargo ship nearly seven weeks ago, was originally set for Saturday, but bad weather forced officials to push the operation to Sunday before it was eventually rescheduled for 5 p.m. Monday, the Coast Guard said.

The planned demolition will help officials remove debris and ultimately free the 213-million-pound Dali cargo ship, which veered off course March 26 and struck a pillar of the Francis Scott Key Bridge, causing it to fall into the Patapsco River below.

The collapse killed six construction workers and destroyed a key thoroughfare, threatening the economy at the Port of Baltimore. It also sparked multiple investigations into what went wrong and who is responsible. Monday’s planned demolition comes days ahead of a Wednesday hearing scheduled by the House Committee on Transportation and Infrastructure, with testimony expected from the chair of the National Transportation Safety Board and officials from the Coast Guard, Army Corps of Engineers and the US Department of Transportation.

“We will absolutely not sacrifice safety for speed,” the Coast Guard’s Nick Ameen said Sunday of the weather delay. “Whenever there’s a lightning strike in the area, that pushes the clock back, and so that clock just kept getting pushed back and pushed back.”

The 21 members of the ship’s crew – who have not left the ship since it struck the bridge – will remain onboard during the operation, according to Darrel Wilson, a spokesperson for Synergy Marine Group, which manages the Dali.

“They will have a safe place on the vessel where they can shelter during the controlled explosion,” Wilson said, adding the crew was “holding up well” despite the stress of recent weeks.

“Even though they are not sailing, they are still performing their normal crew duties,” Wilson said. “This is still a large, complicated piece of equipment and there is a lot they have to look after.”

Officials began moving forward with the demolition process after the body of the sixth and final victim was recovered from the water last week.

If the operation succeeds, the ship could be refloated and returned to the Port of Baltimore as soon as this week, The Baltimore Sun and CNN affiliate WBAL previously reported.

Demolition will sound like fireworks

“The safest and swiftest method to remove the bridge piece from on top of the M/V Dali is by precision cuts made with small charges,” the Key Bridge Response Unified Command said in a news release last week.

“This is an industry-standard tool in controlled demolition that will break the span into smaller pieces,” it added, “which will allow the work of refloating the vessel and removing it from the federal channel.”

The demolition process will “look like multiple puffs of smoke and sound like fireworks,” according to an infographic from the US Army and the US Army Corps of Engineers. Nearby communities should receive a “cellular notification” beforehand, according to Unified Command, which includes state and federal authorities, the US Coast Guard and Army Corps of Engineers among them.

While engineers tackle the logistics of clearing a tangled mess of metal to free the Dali, members of Baltimore’s seafaring community remain concerned for the crew’s well-being given the length of time they’ve been aboard the ship.

The crew is well taken care of but feels disconnected from the rest of the world, Rev. Josh Messick, executive director of the Baltimore International Seafarers’ Center, told CNN. They have internet access, thanks to hotspots Messick’s group helped deliver, but they do not have their cell phones, which were confiscated by authorities as part of the investigation.

“They are a little anxious because of the phone situation. We are trying to get their cell phones back to them,” Messick said. “It’s not just a phone, they can’t access their online banking, their finances, their contacts, they can’t look at photos of their loved ones before they go to sleep at night. It’s a lot more than just a phone.”

CNN’s Paradise Afshar, Holly Yan and Dakin Andone contributed to this report.