OSHA 300A Annual Summary: Deadlines, Calculations, and Common Mistakes

The OSHA Form 300A — the "Summary of Work-Related Injuries and Illnesses" — is a single-page form that distills your entire year of recordkeeping into a handful of totals. Unlike the 300 log, which lists each individual case, the 300A shows only aggregate numbers: how many cases occurred, how many involved days away or restriction, how many total days were lost, and how many hours your employees worked. It must be completed, certified by a company executive, and posted where your employees can see it every year.

The form is straightforward, but the process around it has more requirements than most employers realize. There are three separate deadlines, a specific list of people who are legally authorized to sign it, a calculation for total hours worked that is frequently done wrong, and — for many employers — an electronic submission requirement that carries its own penalties for noncompliance.

The Three Deadlines

The 300A cycle involves three dates that recur every year. Missing any of them is a citable violation.

February 1 — Post the Summary

By February 1, you must post the previous year's completed and certified 300A summary in a conspicuous location at each establishment — the same area where you post other employee notices such as the OSHA "It's the Law" poster, minimum wage notices, and similar required postings. The summary must be displayed where employees can see it without having to ask for access. A locked office that employees do not regularly enter does not qualify.

March 2 — Electronic Submission (If Required)

If your establishment meets the size and industry thresholds for electronic reporting, you must submit your 300A data — and in some cases your 300 and 301 data — through OSHA's Injury Tracking Application by March 2. The ITA opens for submissions on January 2 each year. Establishments with 250 or more employees in most industries, and establishments with 20 to 249 employees in designated high-hazard industries, must submit 300A data. Establishments with 100 or more employees in certain high-hazard industries must also submit case-level 300 and 301 data.

April 30 — Take Down the Summary

The 300A must remain posted until at least April 30. You may leave it up longer if you choose, but you cannot take it down before this date. The three-month posting window — February 1 through April 30 — gives employees a reasonable period to review the summary.

Completing the Form: Field by Field

The 300A has four sections. Each one pulls data from a specific place, and the numbers must be internally consistent with your 300 log.

Establishment Information

Enter your establishment's legal name, street address, industry description, Standard Industrial Classification (SIC) or NAICS code, and the annual average number of employees. The annual average is calculated by adding your total employment for each month and dividing by 12. If the establishment was not open for the full year, divide by the number of months it was in operation.

Number of Cases

Transfer the year-end totals directly from your 300 log. The 300A asks for four numbers: total deaths, total cases with days away from work, total cases with job transfer or restriction, and total other recordable cases. These correspond to the classification columns G through J on your 300 log. The four numbers should add up to your total number of recordable cases for the year. If they do not match your 300 log totals, you have an error in one document or the other — find and fix it before certifying.

Number of Days

Enter the total number of days away from work (the sum of all entries in Column K of your 300 log) and the total number of days of job transfer or restriction (the sum of Column L). These are aggregate totals across all cases for the year.

Injury and Illness Types

Enter the total number of injuries (from Column M-1 of your 300 log) and the totals for each illness category: skin disorders (M-2), respiratory conditions (M-3), poisonings (M-4), hearing loss (M-5), and all other illnesses (M-6). The sum of all six categories should equal your total number of recordable cases.

Calculating Total Hours Worked

The 300A requires you to enter the total hours worked by all employees during the calendar year. This is the single most error-prone field on the form, and it has outsized consequences because it is the denominator in your TRIR and DART rate calculations. If your hours are wrong, your rates are wrong — and your rates are what insurers, clients, and OSHA look at.

Include actual hours worked by all employees at the establishment: hourly employees, salaried employees, part-time employees, seasonal employees, and temporary workers whose day-to-day work you supervise. Do not include hours for temporary workers supplied by a staffing agency if the agency supervises them.

Do not include paid time off. Vacation hours, sick leave hours, holidays, and other non-work hours should be excluded. This is where most errors occur — many employers pull hours from payroll systems, which typically include PTO. Payroll hours will overstate your total hours worked, which deflates your incident rates and makes your establishment appear safer than it actually is. If OSHA discovers the discrepancy, it raises questions about the integrity of your entire recordkeeping program.

Executive Certification

The 300A must be certified — signed and dated — by a company executive before it is posted. This is not a formality. The certifying executive is attesting that they have examined the OSHA 300 log and reasonably believe the annual summary is correct and complete. OSHA takes the certification seriously, and having the wrong person sign is a frequently cited violation.

OSHA defines "company executive" narrowly under 29 CFR 1904.32(b)(3). Only the following individuals are authorized to certify the 300A:

• An owner of the company (sole proprietorship or partnership)
• An officer of the corporation
• The highest-ranking company official working at the establishment
• The immediate supervisor of the highest-ranking company official working at the establishment

A safety manager, HR director, or plant manager cannot sign the 300A unless they independently qualify under one of the categories above. In a small business where the owner is present and active, the owner should sign. In a large corporation, a corporate officer or the site's highest-ranking official is the appropriate signer. If you are unsure who qualifies, err toward the more senior person.

Common 300A Mistakes That Lead to Citations

Beyond the certification issue, inspectors frequently find the following errors when reviewing the 300A:

• Totals on the 300A do not match the 300 log. This is the first thing an inspector checks. If your 300A says 3 cases with days away but your 300 log shows 4, you will be asked to explain the discrepancy.
• The form is not posted, or is posted in a location employees cannot easily access. A filing cabinet in the safety manager's office does not count.
• The form is posted but not certified. An unsigned 300A is an incomplete 300A.
• The posting period is wrong. Some employers post the 300A in March and take it down in April, or only post it during the month of February. The required posting period is February 1 through April 30 — the full three months.
• Multi-establishment employers post a single consolidated summary instead of posting a separate 300A at each establishment. Each establishment with employees must have its own 300A posted on-site.
• Hours worked are pulled from payroll instead of calculated from actual hours. This inflates hours, deflates rates, and calls the accuracy of the entire submission into question.

How the 300A Feeds Into Your Incident Rates

The numbers on your 300A are the inputs for your TRIR and DART rate calculations. Your total recordable cases divided by your total hours worked, multiplied by 200,000, gives you your TRIR. Your DART cases divided by total hours worked, multiplied by 200,000, gives you your DART rate. These rates follow your company for years — into insurance renewals, contract bids, and OSHA's own targeting algorithms for programmed inspections.

This is why accuracy matters at every stage. A misclassified case on the 300 log flows into wrong totals on the 300A, which produce incorrect rates, which affect your EMR and your ability to win work. The 300A is the point where all of your recordkeeping discipline — or lack of it — becomes visible in a single set of numbers.

Year-End 300A Checklist

• Review your 300 log for completeness: every recordable case entered within 7 days, all classifications updated to reflect final outcomes, all day counts finalized or capped at 180.
• Total each column on the 300 log and verify the arithmetic.
• Transfer totals to the 300A and cross-check: total cases should equal the sum of columns G through J, and should also equal the sum of all Column M categories.
• Calculate total hours worked using actual hours, not payroll hours. Document your methodology.
• Calculate the annual average number of employees (total employment each month divided by 12).
• Have a qualifying company executive review the 300 log, then sign and date the 300A.
• Post the certified 300A by February 1 in a visible location at each establishment.
• If required, submit data through the ITA by March 2.
• Leave the 300A posted until at least April 30.