The Trench, the Dust, and the Coming Rain
On a 2.4-acre church expansion, a crew is installing a 6-foot-deep sanitary lateral in stiff clay. Two laborers are in the trench; the spoil pile sits 18 inches from the lip; the nearest ladder is 30 feet away; the competent person looked at it at 7:00 a.m. and it has rained since. Forty feet away a mason is dry-cutting 8-inch CMU with a gas-powered saw, and the dust plume drifts toward the trench. The silt fence is torn over 150 feet, a 300-cubic-yard soil stockpile sits uncovered near a storm inlet, and the forecast calls for 1.5 inches of rain in 36 hours. No SWPPP exists; the site will disturb 2.4 acres. The owner's representative says, "We're not in a floodplain, so we don't need permits."
1. Rank the hazards and state exactly what stops work today.
Read the worked answer
1. The trench - imminent danger, stop work now.
- A 6-foot excavation exceeds the 5-foot trigger for a protective system in the OSHA excavation standard (29 CFR 1926 Subpart P, enforced in Nevada under the state plan). In stiff clay the soil may be Type B, but type is a competent-person determination, not a guess. Protection means sloping, benching, shoring, or a trench box - for Type B, sloping no steeper than 1:1; for Type C, 1.5:1.
- Spoil must be set back at least 2 feet from the edge; 18 inches is a violation and adds surcharge load to the wall.
- A ladder must be within 25 feet of lateral travel for every worker; 30 feet fails, and two workers in a 60-foot trench need a second means of egress.
- The competent person's 7:00 a.m. inspection is stale - inspections are required before entry and again after every rain event or other change in conditions. The rain since then voids it.
Order of action: get both laborers out, barricade, re-inspect, install protection and egress, then resume.
2. Dry-cutting CMU - also a stop-work item. The silica standard (29 CFR 1926.1153) Table 1 requires integrated water delivery on handheld masonry saws. Dry cutting a gas saw in an occupied area generates respirable crystalline silica with no engineering control and no respirator program. Wet the cut, or move to a wet saw or vacuum-shroud system, and control the plume so it does not blow into the excavation.
Neither hazard is a "coach and continue" item. Both are citation-grade and, in the trench, potentially fatal.
2. Assess the stormwater and environmental exposure, and respond to the owner's representative.
Read the worked answer
The owner's representative is wrong on the law and wrong on the risk.
- The trigger for construction stormwater coverage is land disturbance of one acre or more, not floodplain location. At 2.4 acres, the project needs coverage under the Construction General Permit and a SWPPP before earth is disturbed. In Nevada that program is administered through NDEP. Floodplain status affects local floodplain permits; it has nothing to do with the CGP threshold.
- A SWPPP is not a binder on a shelf. It requires selection and installation of best management practices, inspection on a defined frequency and after rain events, a trained installer/inspector, recordkeeping, and corrective action with deadlines.
Current conditions are a violation in progress:
- 150 feet of failed silt fence = no perimeter sediment control.
- A 300-CY uncovered stockpile near an inlet = direct sediment discharge path.
- 1.5 inches of rain in 36 hours means sediment will leave the site.
Immediate actions: stabilize and re-anchor the silt fence, cover or set back the stockpile, install inlet protection, inspect and clean the inlet, and document each with photos and a time stamp. Then get the SWPPP prepared and the coverage filed.
Exposure: agency enforcement, stop-work orders, per-day penalties, and - the part contractors underestimate - the general contractor as the site "operator" can carry the liability, not the owner who gave the bad advice.
3. How should the project manager handle the owner's representative and the paper trail, starting today?
Read the worked answer
Treat the representative's statement as a directive risk, not a conversation.
- Written notice within 24 hours, factual and non-accusatory: the site disturbs 2.4 acres; construction stormwater coverage and a SWPPP are required before further disturbance; the owner's position that no permit is needed is noted and the contractor is proceeding to correct the observed conditions to protect the owner.
- Do the protective work now rather than waiting for authorization - sediment controls are the contractor's responsibility to install under the permit, and delay in a 1.5-inch forecast is indefensible. Issue a cost proposal for the added BMPs and the SWPPP preparation, but do not hold the site hostage to the negotiation.
- Document the chain: the representative's statement, the date and time, the foreman's daily report, photos before and after corrective action, the inspection log, and the notice receipt.
- Escalate in writing to the owner's authorized contracting officer, not just the field representative, and copy the insurer if a claim or citation appears likely.
- Do not accept direction to violate. "The owner told us not to" is not a defense to a safety or environmental citation, and it is not a defense to a Board complaint. It is, however, excellent support for a change order - if it is written down.
The pattern the exam is testing: the contractor is the party standing in the excavation and operating the site, so the contractor corrects the condition first and argues about money second.