Table 3. Chemicals used in routine oil and gas development that are classified by the United Nations Globally Harmonized System (GHS) Categories 1 and 2 for acute mammalian toxicitya.
| Chemical name | CASRN | Oral toxicity ratings | Inhalation toxicity ratings | Frequency of use (% events) | Median mass per event (kg) | |||
|---|---|---|---|---|---|---|---|---|
| Rat | Mouse | Rabbit | Rat | Mouse | ||||
| 2-Butoxyethanol (Ethylene glycol butyl ether) | 111-76-2 | 4 | 4 | 3 | 2 | - | 26.5% | 545 |
| 5-Chloro-2-methyl-3(2H)-isothiazolone | 26172-55-4 | 4 | - | - | 2 | - | 0.1% | 5.2 |
| DBNPA (2,2-dibromo-3-nitrilopropionamide) | 10222-01-2 | 3 | - | 3 | 1 | - | 0.3% | 4.1 |
| Ethylene oxide | 75-21-8 | 3 | 3 | - | 2 | 3 | 1.0% | <0.1 |
| Ferric chloride | 7705-08-0 | 2 | 4 | - | - | - | 0.5% | 30 |
| Formaldehyde | 50-00-0 | 2 | 2 | - | 2 | 2 | 57.0% | <0.1 |
| Glutaraldehyde | 111-30-8 | 3 | 3 | - | 1 | - | 23.1% | 75 |
| Glycolic acid | 79-14-1 | 4 | 4 | - | 1 | - | 0.1% | 89 |
| Hydrofluoric acid | 7664-39-3 | - | - | - | 2 | 2 | 43.6% | 96 |
| Lithium hydroxide | 1310-65-2 | 3 | 4 | - | 2 | - | 0.2% | 22 |
| Petroleum distillates | 64741-44-2 | - | - | - | 2 | - | 0.1% | 138,679 |
| Propargyl alcohol | 107-19-7 | 2 | 2 | - | 3 | - | 53.8% | 3.7 |
| Sulfuric acid | 7664-93-9 | 5 | - | - | 2 | - | 2.1% | <0.1 |
| Tetrasodium ethylenediaminetetraacetate | 64-02-8 | 4 | 2 | - | - | - | 0.3% | <0.1 |
| Thioglycolic acid | 68-11-1 | 3 | 3 | 3 | 1 | - | 0.1% | 98 |
| Toluene | 108-88-3 | 4 | - | - | >4 | 2 | 1.4% | 6.7 |
| Zinc sulfate | 7733-02-0 | 3 | 2 | 4 | - | - | 0.2% | 50 |
aOnly chemicals with valid CASRN could be evaluated.