How to Calculate OSHA Incidence Rate

by Gerald Hanks; Updated September 26, 2017

The U.S. Occupational Safety and Health Administration (OSHA) is the agency charged with enforcing and monitoring compliance of federal workplace safety regulations. A method OSHA employs to measure compliance with these regulations is the calculation of the workplace injury incidence rate. This rate measures how frequently workplace injuries occur at a specific company. The calculation uses data compiled by the Bureau of Labor Statistics (BLS) to measure the safety of a company's workplace in comparison to peers of similar size.

Non-Fatal Injuries and Days Lost

The BLS gives employers forms to complete that allow them to calculate the OSHA incidence rate. These forms include calculating the number of non-fatal injuries or illnesses that occur on the job site, as well as the days lost due to those injuries. The calculation of days lost can include both days when the employee was away from work and in recovery, and days in which the employee's injuries forced a transfer or restrictions in job duties.

Total Hours Worked

Employers must also calculate the total hours worked by all employees. The calculation for "hours worked" does not include vacation days, sick days, parental leave or other forms of paid leave. For non-hourly employees, such as commission-based sales staff, salaried employees or drivers who get paid by the mile, employers can estimate their hours. These estimates can be based on their scheduled hours, or use the baseline figure of eight hours a day. Employers can use their BLS or OSHA forms to determine the hours worked if they have completed their forms, or they can use payroll records if the government forms are not available.

Calculating OSHA Incidence Rate

The calculation of the OSHA incidence rate is pretty simple. The rate is found by multiplying the number of incidents times 200,000, then dividing that product by the Total Hours Worked:

(Incidents X 200,000) / Total Hours Worked = Incidence rate

The 200,000 figure comes from multiplying 40 hours a week by 50 weeks a yea_r for _100 employees:

40 hours/week x 50 weeks/year = 2,000 hours/year/employee

2,000 hours/year/employee x 100 employees = 200,000 hours/year

Incidence Rate Example

Suppose ABC Construction Company has 300 full-time employees. Those employees suffered 15 non-fatal injuries during 2014. The incidence rate is calculated as:

(15 x 200,000)/600,000 = 3,000,000/600,000 = 5.0

By comparison, XYZ Construction Company has 400 full-time employees. Those employees suffered 18 non-fatal injuries in the same year. The incidence rate is calculated as:

(18 x 200,000)/800,000 = 3,600,000/800,000 = 4.5

Although XYZ had more injuries, ABC had a higher incidence rate.

About the Author

Living in Houston, Gerald Hanks has been a writer since 2008. He has contributed to several special-interest national publications. Before starting his writing career, Gerald was a web programmer and database developer for 12 years. He also started Story Into Screenplay, a screenwriting blog at www.StoryIntoScreenplay.com.