Conflicting Clues at the Ditch

Trust neither exclusively, and report both.

• The shipping paper is the legally required identification document and it must be with the shipment and accessible to responders; its basic description gives the UN number, proper shipping name, hazard class, and packing group. That makes it the best single source.
• But a placard represents the hazard class of the loaded material, and a pail on the ground with a corrosive label means this may be a mixed or multi-load shipment, that the driver may be carrying more than the paperwork shows, or that the placard is simply wrong. A corroded placard that shows only one class is also consistent with the original placard having had more than one class.
• The resolution is not to pick a winner. Adopt the most protective combined hazard profile: a flammable liquid that contains methanol (burns with a hard-to-see flame, toxic by inhalation and skin absorption) and a corrosive material. Verify against drum markings and UN numbers, labels, any SDS the driver has, and by asking the driver what else is aboard. If the conflict survives that, treat it as unidentified material.

Report to dispatch: mixed/conflicting identification, UN 1993 with methanol, corrosive material also present, one symptomatic patient, and a request for the hazmat team and EMS with decon capability.

The driver is a potentially contaminated patient, not a bystander.

• Move him upwind and out of the drainage path, but do not seat him in your cab, in an ambulance patient compartment, or anywhere he will transfer product. Direct him to stay in a designated area until EMS arrives and tell EMS he came out of the cab of a leaking load, is coughing, and has eye irritation. Removal of outer clothing and gross decon belongs in the plan before he is transported.
• The farmhouse is the bigger problem. It is downhill, and methanol is miscible in water, so it travels with runoff rather than floating. The well is the exposure pathway that matters more than the vapor cloud.
• Notify the IC and request that the residents be advised: shelter with windows closed, do not drink, cook with, or bathe in well water, and do not come down to the scene. Route any evacuation upwind and uphill, not past the wreck.
• Notify the water authority or public health agency through the IC. Do not flush the ditch, do not dam it, and do not enter the farmhouse - there is no indication the interior is contaminated, and entering a structure to evacuate without air monitoring is outside your scope.

Distance comes from a source, not from judgment in the moment.

• Use the ERG: Table 1 gives initial isolation and protective action distances by UN number and by spill size. Twelve drums and 660 gallons is a large spill, so the larger distance applies, and the isolation is set in all directions and then adjusted to keep responders upwind and uphill.
• The orange-bordered guide for the UN number tells you what the material does (fire/explosion vs. health) and where the protective action distances are indexed from.
• If the product changes, the answer changes to a new UN number - not to a smaller number that feels safer. A driver's verbal correction is a reason to re-read the shipping paper, look at the drum markings and labels, and pull the guide for the new UN number. If the new description cannot be pinned to a UN number and a guide, you revert to the unknown-release recommendation, hold the larger perimeter, and let the hazmat team refine it on arrival.
• Never shrink an isolation zone to make traffic or the farmhouse more convenient. Expansion is cheap; a responder inside a flammable vapor envelope is not.