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United Nations/North American Number Datasheet

UN/NA 1929

4.2 - Spontaneously combustible

Emergency Response Guidebook (ERG, 2024)

The Emergency Response Guidebook (ERG) provides general response recommendations for first responders.

UN/NA datasheets display several items from the ERG: material names, response guide PDFs, initial isolation and protective action distances, warnings about toxic-by-inhalation gases that may be produced if the material spills in water, and polymerization hazards.

A caution icon. The ERG recommendations are developed for use during the initial phase of transportation incidents; they are not intended for spills at facilities.

Material Names

  • Potassium dithionite
  • Potassium hydrosulfite
  • Potassium hydrosulphite
ERG book cover

Response Guide 135

link to a PDF file Substances - Spontaneously Combustible

 

ERG Table 1: Initial Isolation and Protective Action Distances

Name of Material Small Spills
(from a small package or small leak)
Large Spills
(from a large package or many small packages)
First
Isolate
in all Directions
Then Protect Downwind First
Isolate
in all Directions
Then Protect Downwind
Day Night Day Night
Potassium dithionite (when spilled in water) 100 ft 0.1 mi 0.2 mi 200 ft 0.3 mi 1.2 mi
Potassium hydrosulfite (when spilled in water) 100 ft 0.1 mi 0.2 mi 200 ft 0.3 mi 1.2 mi
Potassium hydrosulphite (when spilled in water) 100 ft 0.1 mi 0.2 mi 200 ft 0.3 mi 1.2 mi

ERG Table 2: Water-Reactive Materials which Produce Toxic-By-Inhalation Gases

When spilled in water, large amounts of Hydrogen sulfide (H2S) and Sulfur dioxide (SO2) may be produced.

Map the ERG's Initial Isolation and Protective Action Distances

Use this tool to see the ERG green table values (above) on a map, and you can also export the map objects as a KML file. See the ERG Distances (PDF) for information on using these values and how they were created.

Set the spill location by typing an address or coordinates into the box in the panel, or by clicking a location on the map. Then use the choices in the panel to provide additional details about the release.

See data entry hints

Note: These distances are for spills where there is no fire involved.

If the substance is on FIRE
When a fire is involved, the ERG developers state that you should use EVACUATION value in the appropriate orange ERG Response Guide for the initial isolation distance. Then also PROTECT in the downwind direction according to the green Table 1 (or Table 3) value for residual material release.

Hazmat Table (49 CFR 172.101)

The Hazmat Table in 49 CFR 172.101 "lists and classifies those materials which the Department (of Transportation) has designated as hazardous materials for purposes of transportation".

UN/NA datasheets display several items from the Hazmat Table: proper shipping names, hazard classes and divisions (explosives may also include a compatibility group letter label codes, and special notes relating to shipping location, shipping name, and whether the material is an inhalation hazard.

Descriptive text for each label code is shown below the table, along with representative vehicle placards.

UN/NA Proper Shipping Name Hazard Class Labels Notes*

* There are three notes: (1) whether the displayed information is for domestic (U.S.) or international shipping (if neither is specifically indicated, it applies to both), (2) whether the proper shipping name must include one or more technical names of the hazardous material in parentheses, and (3) whether the hazardous material is an inhalation hazard.
UN Potassium dithionite or Potassium hydrosulfite 4.2 4.2

  4.2 - Spontaneously combustible