CHST question for October 26, 2026

The CHST question of the day for Monday, October 26, 2026, on incident rate calculations. Pick an answer to see the explanation and its source.

CHST Domain 3: Safety Program Development, Implementation, and Sustainment

A manufacturing plant logged 15 OSHA-recordable injury and illness cases last year. Its 420 employees worked a total of 814,000 hours. Use rate = (number of cases × 200,000) ÷ total hours worked. What is the plant's total recordable incidence rate per 100 full-time workers?

Show answer and source: BLS, How To Compute Your Firm's Incidence Rate for Safety Management

Answer: B. 3.69

Incidence rate = (N x 200,000) / hours worked = (15 x 200,000) / 814,000 = 3.69. The 200,000 base represents 100 employees working 40 hours a week for 50 weeks. Using 100,000 as the base would give half the correct value.

On the job

A safety coordinator at a warehouse needs to compare the site's injury record against an industry benchmark. Total recordable cases are multiplied by 200,000 and divided by total employee hours worked, which gives a rate per 100 full-time workers. The 200,000 base equals 100 employees working 40 hours per week for 50 weeks, so the result lines up with the benchmark's standard base.

Study aid, not site-specific safety advice. The official rule controls.

Answer B comes from

BLS, How To Compute Your Firm's Incidence Rate for Safety Management

“(Number of injuries and illnesses X 200,000) / Employee hours worked = Incidence rate (The 200,000 hours in the formula represents the equivalent of 100 employees working 40 hours per week, 50 weeks per year, and provides the standard base for the incidence rates.)”