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Toolbox talk · 10 min · Excavation & Trenching

Call 811 Before You Dig

Hazards: Natural gas or fuel line strike (fire, explosion) · Electrocution from a buried electric cable · Fiber, water and sewer line damage · Struck-by from an uncontrolled release

Why it matters

In its 2024 DIRT Report, published in September 2025, the Common Ground Alliance analyzed 196,977 unique damage reports to buried utilities. The single largest root cause was failure to notify 811 — about one damage in four. That is not a locator problem. That is a crew starting a dig before anyone made the call. A gas line at the wrong end of a bucket does not give you a second decision.

Key points

  • Locate before the excavation is opened. 1926.651(b)(1): the estimated location of sewer, telephone, fuel, electric, water and anything else reasonably expected to be encountered is determined prior to opening the excavation.
  • 811 is the number, the ticket is the proof. OSHA's Excavations booklet names calling 811 as the common industry practice. Ticket number on the permit, and know the date it expires.
  • Know the colors. Red electric, yellow gas and fuel, orange communication, blue potable water, purple reclaimed and irrigation, green sewer and drain, white the dig, pink survey or unknown. A missing color is a missing utility, not a clear dig.
  • Marks are an estimate, not a blueprint. 1926.651(b)(3): approaching the estimated location, the exact location is determined by safe and acceptable means — hand dig or vacuum excavate in the tolerance zone. Teeth verify nothing.
  • Private lines are on us. The ticket covers member facilities. Site lighting, propane, irrigation, the feed to the shop: nobody marks those unless somebody hires a private locator.
  • Protect what stays in the ground. 1926.651(b)(4): while the excavation is open, exposed installations are protected, supported or removed. A pipe hanging unsupported across the trench is a hazard to everyone under it.
  • Any contact stops the job. Strike, scrape or nicked coating: stop, get out and upwind, call 911 and the owner. No ignition sources, no patching, no backfilling over it.

Do / Don't

Do

  • Check the ticket number and expiration before the first bucket.
  • Photograph the marks at the start of the shift.
  • Re-notify when marks are faded, gone or expired.

Don't

  • Assume yesterday's ticket covers today's new dig area.
  • Read a paint line as the exact centerline or the exact depth.
  • Dig freely around a line because somebody called it abandoned.

Quick site check

  • Ticket number, expiration date, and which utilities responded — who has that right now?
  • Walk the dig limits: are the white marks readable, and is every expected color present?
  • Which lines do we expose today, and how do we support them once they are open?
Discussion — ask the crew
  1. Who on this crew actually placed the locate ticket for the dig we start today, and where is the ticket number written down?
  2. Walk the dig in your head: what marks are on the ground right now, and which colors are missing that should be there?
  3. Where are the private lines on this property — yard lighting, propane, irrigation, the shop feed — and who owns finding them?
  4. What do we do, in order, the second the bucket teeth touch something we did not expect?
Refs: 29 CFR 1926.651(b) — Underground installations (locate, notify, verify, protect) · OSHA Publication 2226 — Excavations (names 811 as the common industry practice) · FCC — 811 designated as the nationwide call-before-you-dig number · CGA Best Practices Appendix B — APWA Uniform Color Code (ANSI Z535.1) · Common Ground Alliance — 2024 DIRT Report (published September 2025) · PHMSA — Call Before You Dig / one-call programSign-in sheet included in the printed version

Frequently asked questions

OSHA requires the result, not the phone call. 29 CFR 1926.651(b)(1) requires the estimated location of utility installations to be determined before opening an excavation, and (b)(2) requires utility owners to be contacted and asked to establish those locations. OSHA's own Excavations booklet (Publication 2226) then says that one common industry practice is to call 811, the Call Before You Dig number. State one-call law is what usually makes the ticket mandatory, and the penalties there are separate from OSHA's.

That comes from state law, not from OSHA, and it varies — commonly two to three working days. What 1926.651(b)(2) says is that utility owners must be contacted within established or customary local response times. If they cannot respond within 24 hours, unless state or local law allows longer, or cannot establish the exact location, the employer may proceed with caution using detection equipment or other acceptable means.

The APWA Uniform Color Code, adopted in CGA Best Practices Appendix B and keyed to ANSI Z535.1: red is electric power, yellow is gas, oil, steam or petroleum, orange is communication, alarm and signal, blue is potable water, purple is reclaimed water and irrigation, green is sewer and drain, white is the proposed excavation, and pink is temporary survey marks or an unknown facility. States may add requirements of their own.

It is the band on either side of a locate mark where mechanical excavation is not appropriate. Its width is set by state law — often 18 or 24 inches from the outside edge of the marked facility. Inside it, 1926.651(b)(3) applies: when excavation approaches the estimated location, the exact location shall be determined by safe and acceptable means, which on most jobs means hand digging or vacuum excavation.

Usually not. The one-call ticket reaches the member facility owners on the public system. Yard lighting, propane tanks, septic, irrigation, a feed running from a building to a shop or a sign — those are typically the property owner's and stay unmarked unless a private locator is hired. 1926.651(b)(1) still covers them: the estimated location of any other underground installations reasonably expected to be encountered has to be determined before the excavation is opened.

Stop work, get everyone out and upwind, and call 911 and the facility owner from a safe distance. Do not try to pinch, plug, cap or backfill over a struck gas line, and do not operate anything that could be an ignition source, including the machine that made the contact. Report even a scrape or a nicked coating: damage that is buried and forgotten is what causes the failure months later.

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