2.6 Hazard Information Sources & Field Reference Systems
Key Takeaways
- The DOT Emergency Response Guidebook is revised every four years — the current edition is ERG2024 — and is built for the first 30 minutes of a transportation incident, not for long-term site work.
- ERG navigation is color-coded: yellow pages index by four-digit UN/NA number, blue pages index alphabetically by material name, orange pages hold the 62 numbered response guides, and green pages give initial isolation and protective action distances.
- The NIOSH Pocket Guide to Chemical Hazards supplies the field values an SDS often omits: the NIOSH REL, the OSHA PEL, the IDLH concentration, incompatibilities, and specific respirator recommendations.
- CHEMTREC (1-800-424-9300) provides 24-hour chemical emergency information; the National Response Center (1-800-424-8802) is the federal point of contact for reporting a release.
- Appendix E to 1910.120 requires the 40-hour course to cover sources of hazard information and exercises using relevant manuals and hazard coding systems.
Hazard Information Sources & Field Reference Systems
Appendix E to 1910.120 lists "sources for additional hazard information" and "exercises using relevant manuals and hazard coding systems" as a required technical skill for the 40-hour course. Knowing that benzene is a leukemogen is worth little if you cannot find its IDLH in ninety seconds while wearing gloves. This section covers what to reach for, in what order, and what each source will and will not tell you.
The Decision Rule: Which Source, When
| Situation | First source | Why |
|---|---|---|
| Unknown material in transport, placard or UN number visible | DOT Emergency Response Guidebook (ERG) | Built for the first 30 minutes; gives isolation distances immediately. |
| Known chemical, planning exposure controls and respirator selection | NIOSH Pocket Guide (NPG) | Gives REL, PEL, IDLH, incompatibilities, and specific respirator recommendations. |
| Known product, need manufacturer-specific handling and first aid | Safety Data Sheet (SDS) | 16-section format; Section 8 for exposure controls, Section 4 for first aid. |
| Material unidentifiable, shipper unknown, incident escalating | CHEMTREC, 1-800-424-9300 | 24-hour access to shipper and manufacturer technical specialists. |
| A reportable quantity has been released | National Response Center, 1-800-424-8802 | Federal notification point under CERCLA and the Clean Water Act. |
The DOT Emergency Response Guidebook (ERG)
The ERG is developed by the Pipeline and Hazardous Materials Safety Administration (PHMSA) with Transport Canada and Mexico's transport secretariat, and it is revised on a four-year cycle — the current edition is ERG2024. Every responder should assume any copy on a truck is one edition out of date until proven otherwise.
Its power is its color-coded navigation:
- White pages (front): how to read shipping papers, hazard classification, placard and label charts, rail car and road trailer identification silhouettes, and general safety precautions.
- Yellow pages: materials indexed numerically by their four-digit UN/NA identification number. Use these when you can read the number off a placard, an orange panel, or a shipping paper.
- Blue pages: the same materials indexed alphabetically by name. Use these when you have a name from a manifest or a driver but no number.
- Orange pages: the 62 numbered response guides (Guide 111 through Guide 172). Each guide is a two-page spread structured identically — Potential Hazards (fire/explosion and health, ranked in order of severity), Public Safety (isolation, protective clothing, evacuation), and Emergency Response (fire, spill or leak, first aid). Guide 111 is the default for a mixed load or unidentified cargo.
- Green pages: Table 1 gives initial isolation and protective action distances for toxic-inhalation-hazard (TIH) materials, split by small versus large spill and by day versus night; Table 2 lists water-reactive materials that produce toxic gases; Table 3 gives distances for large quantities of six common TIH gases in specific container types.
- White pages (back): protective clothing guidance, BLEVE safety, criminal/terrorist incident guidance, glossary, and emergency contact numbers.
The ERG2024 revision added guidance for electric-vehicle and lithium-ion and sodium-ion battery incidents, a decision table for evacuate-versus-shelter-in-place, and a QR code linking to incident reporting.
Know the ERG's limits. Isolation distances are conservative first-30-minute defaults, not a substitute for air monitoring and plume modeling. The ERG covers materials in transportation — it will not help you with an unlabeled 40-year-old drum pulled out of a landfill, which is what the sampling and HAZCAT workflow in Section 6.3 exists for.
The NIOSH Pocket Guide to Chemical Hazards
The NIOSH Pocket Guide (NPG) condenses roughly 677 chemicals into a standard one-page-per-chemical layout. The last full printed edition is the 2007 printing of DHHS (NIOSH) Publication No. 2005-149; NIOSH maintains the authoritative current version online and in mobile form, so verify values against the online entry.
For each chemical the NPG gives:
- Chemical name, synonyms, CAS number, RTECS number, DOT ID and guide number — which is how you jump from the NPG straight into the correct ERG orange guide.
- Exposure limits: the NIOSH REL, the OSHA PEL, and the IDLH concentration. The IDLH value in particular is frequently missing from commercial SDSs, and it is the number that decides whether an air-purifying respirator is permitted at all (see Section 5.2).
- Physical description, molecular weight, boiling point, freezing point, solubility, vapor pressure, ionization potential, specific gravity, flash point, LEL and UEL — the properties taught in Section 2.5, in one line.
- Incompatibilities and reactivities — the segregation data you need before bulking or lab-packing.
- Measurement methods (NIOSH or OSHA sampling and analytical method numbers), personal protection and sanitation, respirator recommendations keyed to concentration, exposure routes, symptoms, target organs, and first aid.
Shipping Papers, Manifests, Placards, and UN/NA Numbers
- DOT shipping papers must state the basic description in sequence: identification number, proper shipping name, hazard class or division, and packing group, plus quantity and a 24-hour emergency response telephone number. On a truck the papers are in the cab; on a rail car they are with the train crew as a consist or waybill.
- The EPA Uniform Hazardous Waste Manifest (EPA Form 8700-22) is the cradle-to-grave tracking document that follows a waste shipment from generator through transporter to the designated receiving facility, and is now filed electronically through EPA's e-Manifest system. It tells you what a site shipped; historical manifests recovered during the Phase 1 assessment in Section 3.1 are among the best predictors of what is buried there.
- Placards carry the DOT hazard class number at the bottom, a symbol at the top, and often the four-digit UN/NA number in the center or on an adjacent orange panel. That four-digit number is your entry point into the ERG yellow pages.
- NFPA 704 and HMIS in-plant systems are covered in Section 2.4. Remember the direction reversal: 4 is worst in NFPA and HMIS, while GHS Category 1 is worst.
Additional Authoritative Sources
- ATSDR Toxicological Profiles and ToxFAQs for chronic and community health effects of legacy contaminants.
- EPA's CAMEO suite — CAMEO Chemicals for reactivity prediction between mixed materials, ALOHA for plume modeling, MARPLOT for mapping.
- Poison control, 1-800-222-1222, for exposure and treatment guidance to relay to a receiving hospital.
- The site HASP itself, which under 1910.120(b)(4)(ii)(A) must contain a task-by-task hazard analysis for the specific site you are standing on.
The professional habit to build is layering: use the ERG or placard to bound the problem in the first minutes, the NPG and SDS to select controls and respirators, CAMEO to test whether two waste streams can safely meet, and CHEMTREC or the National Response Center when the situation exceeds your information.
You arrive at an overturned tanker and can read a four-digit identification number on the orange panel, but the driver and shipping papers are inaccessible. Which section of the Emergency Response Guidebook do you use first?
A safety officer must decide whether a full-facepiece air-purifying respirator may legally be used for a known contaminant, but the manufacturer SDS does not list an IDLH value. Which reference is the standard source for that number?
How often is the DOT Emergency Response Guidebook revised, and what is its intended scope of use?