Site Hazards & Emergencies

Excavations

Key risks: collapse of excavation sides; falling materials from surface; people or plant falling in; striking buried services (gas, electricity, water, telecoms).

HSE principle: "No ground can be relied on to stand unsupported."

Precautions: support sides (trench sheets, props, or hydraulic box) OR batter (slope) back to a stable angle; edge barriers and spoil setback; safe access — ladder or ramp within easy reach. Locate buried services using CAT & Genny, trial holes, service drawings; hand-dig within the safe zone of any located service.

Inspection: competent person must inspect at the start of each shift and after any event that may have affected stability. Inspections recorded in writing.

There is no universal depth trigger in law. HSE states risk assessment and actual ground conditions determine precautions. The often-quoted 1.2 m figure is an industry rule-of-thumb only — it is NOT an HSE legal threshold.

Confined Spaces — Confined Spaces Regulations 1997

Three main dangers: (1) lack of oxygen, (2) toxic gas/fume/vapour (e.g. hydrogen sulphide, carbon monoxide), (3) flammable gas/vapour.

Duties: avoid entry where reasonably practicable → safe system of work (permit-to-enter) → emergency/rescue arrangements must be in place BEFORE anyone enters → continuous atmospheric monitoring during occupation where required.

Never rely on 999 as the primary rescue plan. Never enter alone without a permit and atmosphere test. Attempting unplanned rescue has killed many would-be rescuers.

Buried Services — HSG47

Plan: obtain service drawings from all relevant utility companies. Plans give approximate positions only — services may be deeper, shallower, or off-line.

Locate: use a CAT (cable avoidance tool) and Genny repeatedly; dig trial holes by hand to confirm exact position, depth, and type; mark located services on the ground.

Safe dig: use hand tools within the safe zone of any located service; dig alongside the service, not directly above it; use insulated tools near electrical cables; never use a mechanical excavator directly over a located service without hand-dug confirmation.

Overhead Lines — GS6

Confirm the safe clearance distance with the Distribution Network Operator (DNO) before any work begins near overhead lines. You MUST confirm with the DNO — do not assume a single distance applies to all voltages.

A ~6 m exclusion zone is commonly applied as a precautionary measure but is not universally sufficient for all voltages.

Controls: contact the DNO to request the line is made dead, diverted, or insulated; erect goal-post barriers and warning notices; restrict plant height and boom reach. Do not assume a line is de-energised — treat all overhead lines as live until confirmed otherwise. Even 230 V can kill.

Asbestos Awareness — CAR 2012

Asbestos may be present in any building constructed or refurbished before 2000. All three types — white (chrysotile), brown (amosite), blue (crocidolite) — are dangerous.

Golden rule: suspect ACM → STOP work immediately → do NOT disturb or damage → REPORT to supervisor → keep others away.

Duty holder must have a survey to identify ACMs and a written management plan (CAR 2012 Regulation 4). General operatives must never attempt to remove or handle suspected ACMs. Diseases (mesothelioma, lung cancer, asbestosis) have a latency of 15–60 years.

RIDDOR 2013 — Reportable Categories & Deadlines

• Deaths: notify immediately + written report within 10 days.
• Specified injuries (fractures excl. fingers/thumbs/toes; amputations; permanent sight loss; crush injury to head/torso; burns >10% body; scalping; unconsciousness from head injury or asphyxia; 24h+ hospitalisation): notify immediately + within 10 days.
• Over-7-day incapacitation (worker unable to perform normal duties >7 consecutive days — not counting the accident day): written report within 15 days.
• Non-workers taken to hospital from the workplace: within 10 days.
• Occupational diseases (HAVS, occupational asthma, CTS, dermatitis): within 10 days of diagnosis.
• Dangerous occurrences (scaffold collapse, explosion, crane overturn — Schedule 2): notify immediately + without delay.

The old over-3-day reporting rule has been replaced by over-7-day incapacitation. Reports made at hse.gov.uk/riddor. Records kept for 3 years.