Derivation of Hazard Score
The Hazard Score is used to sort the 987 chemical and biological agents in the Agents table of Haz-Map.
First, how great is the risk of industrial exposure? Each chemical gets points for the number of common industrial processes in which exposure could occur from using, mishandling or spilling. Industrial chemicals enter the body usually through either the skin or inhalation routes. Each chemical gets 3 points if it has the ACGIH skin designation and 3 points if it is classified as "TIH" by the North American Emergency Response Guidebook. TIH stands for Toxic Inhalation Hazard, and these volatile and toxic chemicals present the highest inhalation danger to spill responders.
Second, how toxic is the chemical in terms of potency, persistence in the body, carcinogenic potential and injury to target organs? Each chemical gets 2 points for potency if it has a low TLV (< or = to 1 ppm or 1 mg/m3) and 1 point for potency if it has a medium TLV (< or = to 5 ppm or 5 mg/m3).
Examples are shown for the ten chemicals with the highest hazard scores: carbon monoxide, lead, cadmium, mercury, nickel, formaldehyde, arsenic, ethylene oxide, chromium, and sulfur dioxide.
Ten Chemicals with the Highest Hazard Scores |
|||||||||||
|
CRITERIA |
POINTS | CO |
Pb |
Cd | Hg | Ni | HCHO | As | EtO | Cr | SO2 |
|
Associated Processes |
count | 19 |
12 |
13 |
7 |
10 |
12 | 8 |
1 |
14 |
14 |
|
Skin Absorption |
3 |
|
3 |
|
|
||||||
| Inhalation (TIH) | 3 | 3 | 3 | 3 | |||||||
| Bioaccumulates | 3 | 3 | 3 | 3 | 3 | 3 | 3 | ||||
|
Low TLV |
2 |
|
2 |
2 |
2 |
|
2 | 2 |
2 |
2 |
|
|
Medium TLV |
1 |
|
1 |
|
1 | ||||||
|
Organophosphate |
3 |
||||||||||
|
Organochlorine |
3 |
||||||||||
|
Carbamate |
2 |
||||||||||
|
Chemical Asphyxiant |
3 |
3 |
|
||||||||
|
Simple Asphyxiant |
2 |
||||||||||
|
IARC Known Carcinogen |
3 |
3 |
3 |
3 | 3 | * | |||||
|
IARC Probable |
2 |
2 | |||||||||
|
IARC Possible |
1 |
|
1 | ||||||||
|
Reproductive Toxin |
3 |
3 |
3 |
3 |
3 |
||||||
|
Skin Burns |
2 |
2 |
|
2 |
* | ||||||
|
Allergic Dermatitis |
2 |
2 |
2 |
2 | 2 |
2 |
|||||
|
Chloracne |
3 |
||||||||||
| Interstitial Fibrosis | 3 | ||||||||||
|
Asthma |
3 |
3 |
3 |
3 |
3 |
||||||
|
Pneumonitis |
3 |
3 |
3 |
3 |
3 |
|
3 |
|
3 | ||
|
Chronic Bronchitis |
3 |
|
3 | ||||||||
| Lung Cancer | 3 | 3 | 3 | 3 | * | ||||||
|
MetHgb, Primary |
3 |
||||||||||
|
MetHgb, Secondary |
1 |
||||||||||
| Aplastic Anemia | 3 | 3 | |||||||||
| Hemolytic Anemia | 3 | 3 | |||||||||
|
Liver, Primary |
3 |
||||||||||
|
Liver, Secondary |
1 |
|
|
1 |
1 |
* |
|||||
Kidney Damage |
3 |
|
3 |
3 |
3 |
* | |||||
|
Peripheral Neuropathy |
3 |
3 |
3 |
3 |
3 |
||||||
|
Parkinson's Syndrome |
3 |
3 | |||||||||
|
CNS Solvent Syndrome |
3 |
||||||||||
|
Totals |
31 |
30 |
30 |
29 |
28 |
26 |
26 |
26 |
24 |
24 | |
*About Chromium Compounds
The score of 22 for chromium is for chromium metal and Cr III compounds. The International Agency for Research on Cancer considers these compounds to be "not classifiable as to carcinogenicity in humans." Chromium VI compounds are classified by IARC as human carcinogens (Class 1). Hexavalent chromium compounds (Cr VI) include:
- Water-soluble compounds: chromium trioxide (chromic acid), and monochromates and dichromates of sodium, potassium, ammonium, lithium, cesium and rubidium;
- Water-insoluble compounds: zinc chromate, strontium chromate and sintered chromium trioxide; [ACGIH]
"NIOSH considers all Cr(VI) compounds (including chromic acid, tert-butyl chromate, zinc chromate, and chromyl chloride) to be potential occupational carcinogens." [NIOSH Pocket Guide Appendix]
"Compounds of CrIII do not cause chrome ulcerations and do not generally initiate allergic dermatitis without prior sensitization by CrVI compounds." [ILO Encyclopedia] Chromates, the most common cause of allergic contact dermatitis, are released as hexavalent chromium from chrome-plated metal tools and machine parts. [Marks & DeLeo, p. 117-9] Animal experiments have associated chromium with birth defects, but there are no studies implicating it as a cause of birth defects in humans. Chronic exposure to hexavalent chromium may produce evidence of kidney and liver injury. [ATSDR Case Studies # 4] Asthma reported in printer, plater, welder and tanner (chromium and nickel); [Chan-Yeung & Malo] Allergic contact dermatitis in agricultural workers, construction workers, mechanics and printers; [Marks & DeLeo]
Revised: February 08, 2004