The leading cause of workplace injury in 2012 was attributed to overexertion in the workplace, according to the Liberty Mutual Research Institute for Safety’s 2014 Workplace Safety Index.

Injuries related to lifting, pushing, pulling, holding, carrying, or throwing represented 25% of the top 10 work hazards, costing US companies $15.1 billion in the same time period.

The index ranks the 10 leading causes of workplace injuries and then associates them with direct workers’ compensation costs. The report draws information from Liberty Mutual’s workers’ comp claims, the US Bureau of Labor Statistics and the National Academy of Social Insurance. Researchers then looked at the BLS injury event coding to see which injuries caused employees to miss six or more days of work. These events were then ranked by total works’ compensation costs.

The top 10 causes are as follows:
1. Overexertion (25 percent, costing $15.1B).
2. Falls on same level (15 percent, costing $9.1B).
3. Struck by object or equipment (9 percent, costing $5.3B).
4. Falls to lower level (9 percent, costing $5.1B).
5. Other exertions or bodily reactions (7 percent, costing $4.27B).
6. Roadway incidents involving vehicles (5 percent, costing $3.18B).
7. Slip or trip without fall (4 percent, costing $2.17B).
8. Caught in/compressed by equipment or objects (4 percent, costing $2.1B).
9. Repetitive motions involving micro-tasks (3 percent, costing $1.84B).
10. Struck against object or equipment (3 percent, costing $1.76B).

In total, the listed injuries amounted to approximately $60 billion in US workers’ comp costs in 2012, the last year this data is available.