How should Legacy handle a historical asbestos survey that found no hazardous airborne concentration?
NIOSH’s 1976 evaluation of 919 Third Garage in Manhattan is useful precisely because it demonstrates how negative evidence should be bounded by the conditions actually sampled.
Documented evidence
- NIOSH evaluated environmental air samples, ventilation and work procedures at 919 Third Garage Company in New York City.
- The report concluded that workers were not exposed to hazardous airborne concentrations of asbestos during the evaluated conditions.
- The same evaluation identified a potential carbon-monoxide hazard, illustrating that a workplace survey can produce different findings for different hazards.
What the record does not establish
This finding is bounded to the evaluated workplace, work practices and survey period. It does not prove the absence of asbestos-containing components or eliminate the possibility of different conditions during other tasks or times.
Why this becomes graph value
The record is published as a reconstruction object, not a list entry. Legacy preserves the source, time context, material or task context, and the boundary between documentation and inference so the same evidence can support more than one historical question without being overstated.
Next reconstruction questions
Useful next questions include: What years? Which building, department, vehicle, machine, trade or maintenance task? What records, specifications, photographs, purchase documents, union records or coworkers can narrow the history?
Primary source
Primary source record Primary / authoritative source