11.6 Hazardous Materials, Weather, Emergency Planning, and Incident Response

Plan for the conditions that interrupt the plan

Incidents rarely come from misunderstanding a pruning objective alone. They come from a second condition: fuel spilled near ignition, wind that shifted while a limb hung suspended, heat stress that built slowly, a storm that energized a damaged tree, or a crew that did not know the site address when help was needed. The Safe Work Practices domain expects you to plan for those interruptions before production starts.

Hazardous materials are broader than pesticides

Crews routinely handle gasoline, two-cycle mix, bar and chain oil, hydraulic fluid, solvents, lithium and lead-acid batteries, fertilizers, soil amendments, chromated copper arsenate (CCA) or otherwise treated wood, unknown buried containers, animal waste, and contaminated soil. The control depends on the material, and the governing documents are the product label and the safety data sheet (SDS) — the label is the law for pesticides.

Weather belongs in the briefing and in continuous reassessment

Heat, cold, lightning, wind, rain, ice, smoke, and poor visibility all change the method. Wet bark and rope reduce climbing security; wind alters rigging arcs and aerial-lift stability; rain raises electrical conductivity and degrades braking and footing; cold cuts dexterity; heat impairs judgment. The lightning rule the exam favors: stop exposed work and seek safe shelter when a storm is near, and do not shelter under a tree or stand beside the tallest object.

Know the difference between heat exhaustion (heavy sweating, weakness, nausea — cool and hydrate) and heat stroke (hot skin, confusion, possibly no sweating — a true emergency requiring rapid cooling and EMS).

Emergency planning must be usable under stress

Before work, the crew establishes: the exact site address or location description, the best access point for responders, who calls for help, who meets and guides responders to the patient, where first-aid supplies are, and a rescue plan matched to the work. For climbing or lift work, the plan includes a realistic aerial rescue — a trained crew member who can reach and lower an injured or suspended climber promptly.

"Call 911" is necessary but insufficient: a worker suffering suspension intolerance (orthostatic intolerance) while hanging motionless in a harness can deteriorate in minutes, well before responders arrive, so the ground crew must be able to retrieve or relieve suspension quickly.

Incident response begins with scene safety

The first rule of response is do not become the second victim. Do not rush into an energized area, an unstable tree, a moving-equipment zone, or a traffic lane to help someone before controlling the hazard. Stabilize the scene, shut down equipment, control traffic or pedestrians, call for help with the prepared address and access information, and provide care within training and company procedure.

Documentation and the learning system

Near misses, equipment damage, chemical exposures, and injuries are reported through the employer's process so hazards get corrected. The exam frames this as a learning system: a limb that nearly struck a worker is not a lucky non-event — it is evidence the plan needs improvement.

Worked scenario: A crew is rigging in rising wind near overhead conductors when a thunderstorm appears. The correct sequence: secure or lower the suspended load if it can be done safely and quickly, stop exposed work, move the crew away from the tree and conductors to a safe location, account for everyone, and resume only after the weather and electrical hazards are reassessed — not finishing "because we're almost done" or sheltering under the canopy.

Emergency readiness list

• Identify hazardous materials and required controls before disturbance; keep labels, SDS, spill supplies, and PPE accessible.
• Watch weather and stop work when conditions raise the hazard level.
• Confirm exact address, access, who calls, who guides, first aid, and a height-appropriate rescue plan.
• Stop equipment and secure the scene before providing aid.
• Report incidents and near misses so hazards are corrected.

The practical theme: do not improvise predictable emergencies. Fuel, weather, heat, traffic, electrical exposure, falls, cuts, struck-by events, and allergic reactions are all foreseeable in tree work, and the professional plans the response early enough to act clearly when seconds matter.