Arc flash is nothing to fool with, as we’ve often posted about. Not following safety procedures down to the letter, can lead to catastrophic accidents.
This report of an arc flash accident from the Shakopee Valley News highlights how even the most innocuous tasks can lead to disaster:
A series of missteps by the Shakopee Public Utilities (SPU) crew contributed to the power line accident that injured four linemen last summer, according to findings released this week.
The linemen were testing an underground power cable to the Shakopee women’s prison on July 16 when the accident occurred, badly burning two workers and causing a power outage.
“The new underground cable they were testing was inadvertently energized,” said Electric Superintendent Marv Athmann, who called it the worst accident in his 32 years with SPU.
Investigators surmise that a pole lineman accidentally connected an underground cable to a hot wire instead of a neutral source on the street pole, causing arc flashes at both the pole and a transformer near the prison, where half his crew was working. The men were not electrocuted; rather they were burned from the heat of the arc flashes.
The pole lineman, who was working from a utility bucket, is unable to recall what occurred due to memory loss from the accident, according to SPU. The procedure was common and the group was led by an employee with more than 25 years of experience, Athmann said.
On Tuesday night, SPU staff was scheduled to present the report from the Minnesota division of the federal Occupational Safety and Health Administration (OSHA) to the Shakopee Public Utilities Commission.
Although SPU conducts regular training on proper safety procedures, OSHA cited the SPU because the crew leader did not conduct a hazards briefing before work commenced the morning of the accident.
SPU was also cited because crew members failed to wear all recommended protective gear, which worsened the severity of their injuries.
Two workers did not wear long-sleeved shirts, and one who did had the sleeves rolled up and was injured. Only one employee was wearing a face shield attached to a hard hat, but he did not have it swung down to protect his face.
“We go over this stuff. The safety programs are there and in place, but their guards were down for whatever reason,” said SPU Manager John Crooks, surmising that perhaps the heat or the fact that it was a Monday morning may have contributed to the missteps.
The crew was completing the last part of a two-week project and getting ready to energize the transformer when the accident took place.
OSHA also concluded that the crew did not fully assess the scene before beginning its work.
Had workers covered or disconnected an energized lead wire, it may have prevented the arc flashes from occurring, Athmann explained.
SPU was issued three citations and fined $9,600 by OSHA for the failures. SPU itself had to discipline crew members, which was very difficult, said Crooks.
Crooks said the SPU concurs with OSHA’s findings and considers the fines to be fair.
The OSHA report also confirms early speculation that the July 16 incident involved an arc flash, which overwhelmed the equipment the five-member crew was using.
From the onset, the OSHA investigation was expected to last approximately six months. The workers’ injuries delayed some interviews necessary to the investigation.
SPU and its power agency also conducted investigations.
All the injured linemen have now returned to work, although one is still on light duty. He spent a month in a burn unit at Hennepin County Medical Center in Minneapolis and returned to work a few weeks ago.
Although the workers suffered burn scars, thankfully none were left with a permanent disability, Crooks said.
The accident affected half of a nine-member department. SPU employees cooked meals and took care of household chores for families of the injured workers as they recovered.
“It’s family, just about,” Athmann said of the tightknit SPU.
SPU also appreciates all the phone calls and emails from community members, inquiring how the workers were doing.
SPU has already shared its story with other utilities in hopes of reminding other linemen to always wear their protective gear.
“We don’t want this to happen to anybody else,” said Crooks. “It was horrible.”