Taped-Up Guard and a Wet Cord on a Deck Cut Station
A two-person crew is cutting pressure-treated 2x12 rim joists for a deck. They set a 10 in. sliding compound miter saw on a folding plastic stand in the driveway, with the saw’s rear feet on the concrete and front feet on a 2x4 shim. The 16 ft boards are supported only by a sawhorse at each end. The blade guard is sticking and has been taped up. The saw is plugged into a 14-gauge extension cord that runs across a wet area; the cord’s outer jacket is nicked near the plug. One worker holds the board with his left hand 6 in. from the blade while running the saw with his right; the other stands behind the saw to catch the offcut. Neither wears safety glasses, and the treated dust is blowing toward the open garage. The crew plans to finish before lunch. The saw has a laser guide and a dust bag.
1. Identify the highest-risk hazards in this setup and rank the three you would correct before any more cuts. Explain the failure mode for each, not just the rule.
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Highest-risk hazards: (1) taped-up blade guard. The guard is the primary barrier between the operator’s hand and the spinning blade; taping it up turns a miter saw into an exposed blade, and a slip, kickback, or reach across the table can cause a deep laceration or amputation. Correct first: remove the tape, repair or replace the guard and linkage, and do not use the saw until the guard moves freely. (2) Damaged cord and wet area. A nicked jacket can expose conductors; with a wet floor and a metal saw frame, contact can cause shock or electrocution. Correct second: remove the cord from service, use a GFCI-protected circuit, and route a sound cord overhead or away from water. (3) Unstable saw and unsupported stock. The shim lets the saw rock; a 16-ft board supported only at its ends can sag, bind the blade, and kick back or pull the saw off the stand. Correct third: set the saw on a level, solid stand with all four feet contacting, and support the board every 8–10 ft at the same height, with the cut-off side supported so it does not drop and pinch. Hand placement and catching offcuts are also serious, but these three are the immediate life-safety priorities.
2. Describe how to set up the saw and material support for safe repetitive cutting of 16 ft boards, including electrical protection and personal protective equipment.
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Set the saw on a stable, level stand on firm ground; all four feet should bear, with no shims. If the driveway slopes, move to a level area or use a stand with adjustable legs, not a scrap shim. Support the 16-ft board on both the infeed and outfeed sides with stands set at the same height as the saw table, spaced closely enough that the board does not sag-roughly every 8–10 ft-and arrange the outfeed so the cut-off can fall clear instead of being caught. Clamp or hold the stock against the fence with a hand at least 6 in. from the blade path; never reach across the blade. Stand slightly to one side of the blade, not directly in line with the kickback path. Use a GFCI receptacle or GFCI cord set, inspect the cord, and replace the damaged one; keep cords out of water. Wear safety glasses, hearing protection, and a NIOSH-approved particulate respirator for treated-wood dust. Use the saw’s dust bag or a vacuum, and do not blow dust with compressed air.
3. The worker says treated lumber dust is 'just sawdust' and the outdoor air will clear it. How would you respond, and what housekeeping and PPE controls apply?
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Treated lumber is not just untreated sawdust. Modern residential treated wood is commonly copper-based (ACQ, CA, or similar), and cutting and sanding produce fine dust that can irritate the eyes, skin, and respiratory tract; the preservative components and wood dust itself are reasons to control exposure. Outdoor air helps only if the dust is actually dispersed away from the breathing zone-here it is blowing toward the open garage, so the worker and the garage are in the plume. Use a NIOSH-approved N95 or better respirator when cutting or sanding treated wood, especially for repetitive cuts, plus eye protection and gloves if handling rough stock. Clean up with a HEPA vacuum or wet methods; do not dry-sweep or use compressed air. Wash hands and face before eating or drinking, keep food and drink out of the work area, and bag offcuts and dust for proper disposal. If the saw has a dust port, connect a vacuum; the bag on the saw is a start but not adequate for fine dust. If the worker has asthma or sensitivity, reassign or provide a higher level of protection.