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Toolbox talk · 10 min · Health & Ergonomics

Fatigue and Fitness for Duty

Hazards: Slowed reaction and lapses in attention from sleep loss · Long shifts, night work and rotating schedules · Driving or operating equipment while impaired by fatigue, illness or medication · Crew culture where saying "I'm not right today" is not an option

Why it matters

On September 15, 2023, a paving crew was cleaning road cracks with an air wand. The coworker sitting in the tow truck behind them appeared to fall asleep and stepped on the gas pedal; the truck ran over the worker standing in front of it, who lost a leg and died (OSHA Summary Nr 159955.015). Nobody was drunk and nothing was broken. OSHA's own figures say injury rates run 30 percent higher on night shifts, and 37 percent higher on 12-hour days.

Key points

  • Tired hands still work; tired attention does not. Fatigue takes out judgment and reaction time first, which is exactly what running equipment needs.
  • Nothing caps our hours. No OSHA rule limits a construction or plant shift. Truckers, pilots and rail crews have limits; we have judgment and a supervisor.
  • 7 to 9 hours, and sleep close to the shift. On nights, OSHA says sleep within the 8 hours before you start. Nap under 45 minutes or over 2 hours — nothing in between.
  • The drive home counts. It is part of the shift's risk, and it is where a long day most often ends badly.
  • Fatigue is not the only impairment. Illness, a bad night, and medication that carries a drowsiness warning all belong in the same conversation. Ask a pharmacist about your own; ask the supervisor to change the task.
  • Say it before the shift, not after. "I'm not right today, put me on something else" has to be a normal sentence here, or the crew will keep hearing it too late.

Do / Don't

Do

  • Flag a coworker who is nodding off, kindly and early.
  • Trade the high-risk task away late in a long shift.
  • Pull over and sleep instead of finishing the drive.
  • Read the drowsiness warning on anything you take.

Don't

  • Treat running on four hours of sleep as toughness.
  • Leave a tired operator alone in the seat because the job is behind.
  • Rely on coffee to get through the last two hours on a machine.
  • Diagnose a coworker — report the task risk instead.

Quick site check

  • Who is on day nine or ten without a day off?
  • What is the longest shift scheduled this week, and what equipment gets run at the end of it?
  • Is there somewhere on this site a person could actually rest for fifteen minutes?
  • Does everyone know who to tell, today, if they are not fit to run their machine?
Discussion — ask the crew
  1. How many hours did this crew actually work last week, counting the drive?
  2. What time do people here get up to make this start time, and what time do they get to sleep?
  3. If you were too tired to run the machine safely today, who would you tell — and what would happen next?
  4. Which task on this job would be the worst one to do at the end of a 12-hour shift?
  5. Do we know what our company policy says about medication that comes with a drowsiness warning?
Refs: OSHA — Long Work Hours, Extended or Irregular Shifts, and Worker Fatigue: Hazards (injury rates 18% greater on evening shifts and 30% greater on night shifts; 12-hour days associated with a 37% increased risk of injury) · OSHA — Worker Fatigue: Prevention (what employers can do, fatigue risk management plans, and the sleep guidance: 7-9 hours, naps under 45 minutes or over 2 hours, sleep within 8 hours of a night shift) · OSHA — Worker Fatigue: Limitations on Work Hours (the federal hour limits that exist, and the sectors they cover: FMCSA, FAA, FRA, NRC and VA nurses) · OSHA Accident Search, Summary Nr 159955.015 (September 15, 2023): a paving crew member was run over when the coworker operating the tow vehicle appeared to fall asleep and stepped on the gas pedal · OSHA memorandum, October 11, 2018 — Clarification of OSHA's position on workplace safety incentive programs and post-incident drug testing under 29 CFR 1904.35(b)(1)(iv) · CPWR — The Construction Chart Book, 7th edition (2025), chapter 29: hours worked, overtime and time use in constructionSign-in sheet included in the printed version

Frequently asked questions

OSHA cites research showing accident and injury rates 18 percent greater during evening shifts and 30 percent greater during night shifts compared with day shifts, and that working 12 hours per day is associated with a 37 percent increased risk of injury. OSHA also lists decreased alertness from fatigue as a contributing factor in major industrial disasters.

Not in construction or general industry. The federal hour limits OSHA points to apply to specific sectors: commercial drivers under the Federal Motor Carrier Safety Administration, flight crews under the FAA, railroad employees under the FRA, nuclear facility workers under the NRC, and VA nurses under a 2004 law, plus some state laws on mandatory overtime for nurses. Everywhere else, the schedule is the employer's call — and fatigue is still a recognized hazard.

OSHA's guidance is 7 to 9 hours daily without disruptions, at about the same time each day, and — if you work evenings or nights — sleep within the 8 hours before your shift. It also gives a practical nap rule: keep a nap under 45 minutes or make it longer than 2 hours, so you are not waking up in the middle of a sleep cycle.

Say something before the shift starts, not after the incident. Fatigue is the most common reason, but illness, a rough night, and prescription or over-the-counter medication with a drowsiness warning all count. Nobody on the crew is diagnosing anybody: the crew's job is to flag it to the supervisor and reassign the task, and the employer's policy and, where it exists, the employee assistance program handle the rest.

OSHA's October 11, 2018 memorandum states that 29 CFR 1904.35(b)(1)(iv) does not prohibit post-incident drug testing, including testing to evaluate the root cause of an incident that harmed or could have harmed employees. But if the employer tests for that reason, it should test everyone whose conduct could have contributed to the incident, not only the person who reported an injury — testing only the injured worker would likely violate that paragraph.

CPWR's Construction Chart Book (7th edition, 2025) reports that 23.1 percent of construction workers said they worked overtime in 2023 against 19.5 percent across all industries, and that construction workers spend about 9.1 hours a day on work and work-related activities versus 8.2 hours for the average worker — with slightly less sleep, 8.1 hours against 8.2.

Sources & references

Content checked against these sources — last reviewed August 28, 2026.

Results are estimates for planning purposes and do not replace a competent person's evaluation or an engineer's design. Follow the OSHA standards that apply to your work and your employer's written program.

By — Editorial team of SteelToeTools.com (published by LSEA SAS) Updated