COLUMBIA — Two failures in scaffolding equipment are the reported cause of the accident that killed a bricklayer last November at Alpha Hart Lewis Elementary School's construction site.
The information was released in a report by the Occupational Safety and Health Administration, which closed the case earlier this year.
Alan Hildebrand, a 53-year-old bricklayer working on the construction, was killed Nov. 10 after scaffolding collapsed. He fell two stories to his death, the Missourian reported.
There are two separate causes of the accident, said Gene Robertson, an engineering consultant for Siebert Engineers Inc. of Kansas City and an investigator hired by Missouri Employers Mutual. OSHA used information collected from Robertson's findings to help formulate its report.
“This is a situation where both happened to occur at the same time. If either of the two malfunctions occurred independently, there most likely would not have been an incident,” he said.
One cause of the accident was the secondary cylinder that forces the platform-lifting arm in and out, sometimes causing the arm to stick, Robertson said. When it stuck, the lifting arm did not fully engage the hook, which was resting on the edge of the slot and slipped off.
“When you take the manufacturing variance in the roller and the manufacturing variance in the shaft and then you add the dirt and debris, you get what we call a stacking effect,” Robertson said. “It is not just the fact that you have dirt and debris, but also that you add several things that add up to it all.”
The “stacking effect” created the second cause of the failure of the hydraulic system, which engages the safety dogs, or metal plates. The hydraulic pressure went to zero, causing the collapse of the scaffolding.
If the safety dogs worked, the accident wouldn’t have happened, Robertson said. Instead, the platform would have been stuck in the air.
The owner and maintenance manuals don’t have any specifications as to service, maintenance or cleaning to be performed on the machinery, he said.
“The company that manufactured the scaffolding is out of business – they went out of business six years ago,” Robertson said. “The guy doing repairs has no responsibility. The operator and company owner didn’t do anything wrong. It is an unfortunate accident that I see no wrongdoing.”
Hildebrand, of Ashland, Ohio, was completing the top of the gymnasium wall at the new elementary school when he fell, the Missourian reported.
Hildebrand was an employee of Dean Hathman Masonry Co., which was subcontracted by the district's construction company, Professional Contractors and Engineers Inc.
Hildebrand's relatives have filed a wrongful-death lawsuit, alleging that the scaffolding was defective, The Associated Press reported.
Nick Boren, chief operations officer for Columbia Public Schools, said the district does not make regulations regarding the construction of their schools — it only hires the contractors. Therefore, the district has no control over whether contractors use the type of scaffolding that failed in the case of Hildebrand’s death. That, he said, is a decision left to the contractors.
“We’re not in the business of building schools,” Boren said.
On May 4, several members from Hildebrand’s family, including his mother and his sister, made the trip from Akron, Ohio, to Columbia to visit the site where Hildebrand died. Boren took the family on a tour of the school construction site, where he said they spent about an hour.
“It was very emotional for them,” Boren said.
Boren has been in contact with Hildebrand’s family since the incident and said he is very sorry for their loss.
“The loss of a life is an unbelievably tragic thing,” he said, “and for this family it has been a difficult time.”