OSHA Accident Investigation · Summary #221403553

SUPERIOR TREE SERVICE INC.

MORAGA, CA· 2021-10-20T00:00:00

Event: Abrasion, Arm, Blunt force, Blunt force trauma, Chain Saw, Communication, Contusion, Cutting, Fall, Fall From Elevation, Fall Protection, Falling Object, Fracture, Head, Heat Injury Prevention Program, Inexperience, Misjudgment, Misjudgment of Hazardous Situation, PPE, PPE Hazard Assessment, Rigging, Rope, Struck Against, Struck By, Training, Tree, Tree Care, Tree Felling, Tree Limb, Tree Section
NAICS: 561730
Inspection type: Federal Agency
Activity number: #345591192
Employer profile: SUPERIOR TREE SERVICE INC.
Summary number: 221403553
Report ID: 0950615

Event description

Employee is killed in fall from tree, rigging system fails

Investigation abstract

At 11:20 a.m. on October 20, 2021, an employee was using a chainsaw to cut trees in variables that are hard to account for and the employee needs to be aware of the significant forces generated in the rigging on various components throughout the system. In this case, the employee did not take into account the those forces generated by the cut material on the tree trunk as the material free falls before impacting the anchor point below the load. The free fall multiplies forces greatly; a 100-pound piece of wood can easily generate 1,000 pounds of force after only a short free fall. As a result, the employee was killed when the tree trunk, where the rigging system was attached, snapped from the strain imposed on it by the cut tree section being lowered. Emergency Medical Services was called and tried to revive the employee, who was on the ground with serious at a private residence for a commercial tree service. The employee was working injuries to his left arm. The Homeowner reported that the employee was moaning when he came out of his home to see what had happened and before EMS arrived. Multiple coworkers witnessed the accident. The employer failed to conduct a job briefing, failed to provide appropriate personal protective equipment, and failed to have a qualified tree worker onsite. approximately 46 feet up in a tree cutting an upper section which he was tied to. The tree rigging system the employee was using is known as a negative blocking rigging system, which is also known as butt-hitching or blocking wood. This type of rigging system is possibly one of the most complex of all tree working situations and can involve a vast range of knowledge on subjects such as physics, wood properties, equipment ratings, rope strengths and good working communications between a wide range of staff members. This technique also adds

Victim

#1 Fatality Age 26 M

Event type
5

Occupation code
889

Codes shown verbatim from OSHA's accident-investigation database. A human-readable decoder is coming in a future release once the accident_lookup2 dictionary is loaded.