How this instrument works
TRIR takes every OSHA-recordable case in a period, multiplies it by 200,000, and divides by the hours the workforce actually worked. That constant is not decoration: 100 full-time employees working a standard 40-hour week for 50 weeks log exactly 200,000 hours between them, so the formula rescales any real payroll, however large or small, onto that same shared 100-worker year. A five-person crew and a five-thousand-person plant can each report a TRIR, and the number means the identical thing for both — cases per 100 workers, per year.
General contractors write TRIR ceilings into prequalification packets before a subcontractor is even allowed to bid — miss the cutoff and the paperwork stops there, regardless of price. Public companies in construction, energy and manufacturing publish their trailing TRIR inside annual sustainability reports as a safety-culture indicator investors and rating agencies track year over year, and internal safety teams set the same figure as a bonus-linked target for plant managers. Unlike a narrower rate such as DART, which tracks only the more severe subset of cases, TRIR is the broad number that shows up first in all three of those places, which is exactly why a modest hours-logging error travels furthest when it lands here.
TRIR only counts cases that clear OSHA's specific recordability test — a death, days away from work, restricted duty or transfer, medical treatment beyond first aid, loss of consciousness, or a significant injury a physician diagnoses. A near miss, a first-aid-only scrape, or a case logged on the wrong year's OSHA 300 log will not appear, and padding the incident count with anything short of that test overstates the rate. The figure also carries no severity weighting of its own, and it should never be read against a facility's LTIFR, the parallel rate common outside the United States, without first accounting for the different hourly base each one uses.
- Enter Recordable incidents — every case from the period that clears OSHA's recordability test, pulled from the OSHA 300 log.
- Enter Total hours worked — every hour actually logged by the workforce in the same period, not an estimate from headcount times a standard year.
- Read TRIR (per 100 full-time workers) — the instrument multiplies incidents by 200,000 and divides by hours worked automatically.
- Compare the result against a Bureau of Labor Statistics industry average or a client's prequalification ceiling.
- Change either input to see how one additional incident or a swing in hours worked moves the rate.
Worked example — 5 incidents, 1,000,000 hours
A manufacturing plant with roughly 500 full-time-equivalent workers logged 1,000,000 hours worked across the year, and its OSHA 300 log shows 5 recordable incidents in the same period. Enter 5 as Recordable incidents and 1,000,000 as Total hours worked: the instrument multiplies 5 by 200,000 to get 1,000,000, then divides by 1,000,000 hours worked, returning a TRIR (per 100 full-time workers) of exactly 1.0.
That 1.0 means the plant's rate of recordable injury and illness, rescaled to a common 100-worker year, sits at one case — comfortably inside the range a prequalification packet or an annual sustainability report would treat as a healthy trend line. Hold hours worked steady and double the incident count to 10 instead, and TRIR reaches 2.0, the same linear scaling that lets one number stand in for a plant of any size.
Questions
What counts as an OSHA-recordable incident?
A case clears OSHA's recordability test if it involves a death, days away from work, restricted duty or job transfer, medical treatment beyond first aid, loss of consciousness, or a significant injury or illness a physician diagnoses. A scrape treated with a bandage, a near miss, or an incident nobody logged on the OSHA 300 log does not qualify, and folding any of those into the incident count overstates TRIR.
How does TRIR differ from LTIFR used outside the United States?
LTIFR — Lost Time Injury Frequency Rate — is the international equivalent most companies outside the U.S. report, but it scales incidents against 1,000,000 hours worked instead of 200,000, a fivefold difference in the base. Comparing a U.S. site's TRIR of 2.0 against a European site's LTIFR of 2.0 as though the figures matched would be reading two different scales as one; convert one onto the other's base before setting them side by side.
Does a TRIR of 0 mean the site had no injuries at all?
It means no case cleared OSHA's recordability test in the period, not that nothing happened — a first-aid-only scrape, a near miss, or an incident still under review would not move the number. Zero recordable incidents across any hours worked always returns a TRIR of 0, and it is the figure every safety program is ultimately measured against, but it is a floor built from a specific definition, not a guarantee of zero risk.
Why does hours worked matter as much as the incident count?
TRIR divides by hours worked precisely so a small site and a large one can be compared on the same scale — the same 5 incidents produce a TRIR of 1.0 across 1,000,000 hours but a TRIR of 5.0 across only 200,000 hours, without a single additional injury. Using an estimate, such as headcount times a standard 2,000-hour year, instead of hours actually logged is the most common way this figure drifts from what the OSHA log supports.
What TRIR do contractors typically need to win a bid?
There is no OSHA-set threshold — each general contractor or client sets its own prequalification ceiling, often near or below the Bureau of Labor Statistics average for the trade's industry code, tighter for high-hazard work like roofing or excavation. Landing above the stated ceiling commonly removes a bid from consideration before price is even discussed, which is why safety teams track TRIR year-round rather than calculating it once before a submission is due.
Why might TRIR rise even while DART rate stays flat?
TRIR counts every OSHA-recordable case, including ones needing nothing more than stitches or a course of prescription-strength medication, while DART counts only the narrower set serious enough to cause days away, restricted duty or a transfer. A cluster of minor recordable cases can push TRIR up while DART holds steady — worth checking before assuming a safety program is getting worse.
References
- OSHA — Injury and Illness Recordkeeping and Reporting
- U.S. Bureau of Labor Statistics — Injuries, Illnesses, and Fatalities
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.