TABLE 1 – Biological Indicators of Excessive Exposure (IBE/EE)*
| Substance | CAS Number | Indicator(s) | Collection Time | IBE/EE Value | Remarks |
| 1,1,1 Trichloroethane | 71-55-6 | 1,1,1 Trichloroethane in end-exhaled air | AJFS | 40 ppm | – |
| Trichloroacetic acid in urine | FJFS | 10 mg/L | NE | ||
| Total trichloroethanol in urine | FJFS | 30 mg/L | NE | ||
| Total trichloroethanol in blood | FJFS | 1 mg/L | NE | ||
| 1,3 Butadiene | 106-99-0 | 1,2 dihydro-4 (nacetylcysteine) butane in urine | FJ | 2.5 mg/L | EPNE |
| 1,6 Hexamethylene diisocyanate (HDI) | 822-06-0 | 1,6 Hexamethylenediamine in urine | FJ | 15 µg/g creat. | NE |
| 2-Butoxyethanol | 111-76-2 | Butoxyacetic acid in urine (BAA) (H) | FJ | 200 mg/g creat. | – |
| 2-Methoxyethanol | 109-86-4 | 2-Methoxyacetic acid in urine | FJFS | 1 mg/g creat. | – |
| 2-Methoxyethyl acetate | 109-49-6 | ||||
| 2-Propanol | 67-63-0 | Acetone in urine | FJFS | 40 mg/L | EPNE, NE |
| 2,4 and 2,6 Toluene diisocyanate (pure or mixed isomers) | 58484-9 | 2,4 and 2,6 toluenediamine isomers in urine (H) (sum of isomers) | FJ | 5 µg/g creat. | NE |
| Acetone | 67-64-1 | Acetone in urine | FJ | 25 mg/L | NE |
| Aniline | 62-53-3 | p-Aminophenol in urine (H) | FJ | 50 mg/L | EPNE, NE |
| Methemoglobin in blood | FJ | 1.5% of hemoglobin | EPNE, NE | ||
| Elemental arsenic and its soluble inorganic compounds, except arsine and gallium arsenide | 7440-38-2 | Inorganic arsenic plus methylated metabolites in urine | FS | 35 µg/L | EPNE |
| Benzene | 71-43-2 | S-Phenylmercapturic acid (S-PMA) in urine | FJ | 45 µg/g creat. | EPNE, NF |
| Trans-transmuconic acid (TTMA) in urine | FJ | 750 µg/g creat. | For steel industry, current rule maintained. EPNE, NE | ||
| Tetraethyl lead | 78-00-2 | Lead in urine | FJ | 50 µg/L | – |
| Cyclohexanone | 108-94-1 | 1,2 Cyclohexanediol (H) in urine | FJFS | 80 mg/L | NE |
| Cyclohexanol (H) in urine | FJ | 8 mg/L | NE | ||
| Chlorobenzene | 108-90-7 | 4-Chlorocatechol (H) in urine | FJFS | 100 mg/g creat. | NE |
| p-Chlorophenol (H) in urine | FJFS | 20 mg/g creat. | NE | ||
| Cobalt and its inorganic compounds, including cobalt oxides, but not combined with tungsten carbide | 7440-48-4 | Cobalt in urine | FJFS | 15 µg/L | NE |
| Hexavalent chromium (soluble compounds) | 7440-47-3 | Chromium in urine | FJFS | 25 µg/L | – |
| Chromium in urine (increase during work shift) | AJ-FJ | 10 µg/L | – | ||
| Dichloromethane | 75-09-2 | Dichloromethane in urine | FJ | 0.3 mg/L | – |
| Styrene | 100-42-5 | Sum of mandelic and phenylglyoxylic acids in urine | FJ | 400 mg/g creat. | NE |
| Styrene in urine | FJ | 40 µg/L | – | ||
| Ethylbenzene | 100-41-4 | Sum of mandelic and phenylglyoxylic acids in urine | FJ | 0.15 g/g creat. | NE |
| Ethoxyethanol and ethoxyethyl acetate | 111-15-9 | Ethoxyacetic acid in urine | FJFS | 100 mg/g creat. | – |
| Phenol | 108-95-2 | Phenol (H) in urine | FJ | 250 mg/g creat. | EPNE, NE |
| Furfural | 98-01-1 | Furoic acid (H) in urine | FJ | 200 mg/L | NE |
| Methemoglobin inducers | Methemoglobin in blood | FJ | 1.5% of hemoglobin | EPNE, NE | |
| Elemental mercury | 7439-97-6 | Mercury in urine | AJ | 20 µg/g creat. | EPNE |
| Methanol | 67-56-1 | Methanol in urine | FJ | 15 mg/L | EPNE, NE |
| Methyl butyl ketone | 591-78-6 | 2,5 Hexanedione (SH) (2,5HD) in urine | FJFS | 0.4 mg/L | – |
| Methyl ethyl ketone (MEK) | 78-93-3 | MEK in urine | FJ | 2 mg/L | NE |
| Methyl isobutyl ketone (MIBK) | 108-10-1 | MIBK in urine | FJ | 1 mg/L | – |
| Carbon monoxide | 630-08-0 | Carboxyhemoglobin in blood | FJ | 3.5% of hemoglobin | EPNE, NE, NF |
| Carbon monoxide in end-exhaled air | FJ | 20 ppm | EPNE, NE, NF | ||
| n-Hexane | 110-54-3 | 2,5 Hexanedione (SH) (2,5HD) in urine | FJ | 0.5 mg/L | – |
| Nitrobenzene | 98-95-3 | Methemoglobin in blood | FJ | 1.5% of hemoglobin | EPNE, NE |
| N-Methyl-2-pyrrolidone | 872-50-4 | 5-Hydroxy-N-methyl-2-pyrrolidone (SH) in urine | FJ | 100 mg/L | – |
| N,N-Dimethylacetamide | 127-19-5 | N-Methylacetamide in urine | FJFS | 30 mg/g creat. | – |
| N,N-Dimethylformamide | 68-12-2 | Total N-methylformamide in urine (sum of N-methylformamide and N-(hydroxymethyl)-N-methylformamide) | FJ | 30 mg/L | – |
| N-Acetyl-S-(N-methylcarbamoyl) cysteine in urine | FJFS | 30 mg/L | – | ||
| Ethylene oxide | 75-21-8 | N-(2-Hydroxyethyl) valine (HEV) adducts in hemoglobin | NC | 5,000 pmol/g hemog. | NE |
| Carbon disulfide | 75-15-0 | 2-Thioxothiazolidine-4-carboxylic acid (TTCA) in urine | FJ | 0.5 mg/g creat. | EPNE, NE |
| Tetrachloroethylene | 127-18-4 | Tetrachloroethylene in end-exhaled air | AJ | 3 ppm | – |
| Tetrachloroethylene in blood | AJ | 0.5 mg/L | – | ||
| Tetrahydrofuran | 109-99-9 | Tetrahydrofuran in urine | FJ | 2 mg/L | – |
| Toluene | 108-88-3 | Toluene in blood | AJFS | 0.02 mg/L | – |
| Toluene in urine | FJ | 0.03 mg/L | – | ||
| Ortho-cresol in urine (H) | FJ | 0.3 mg/g creat. | EPNE | ||
| Trichloroethylene | 79-01-6 | Trichloroacetic acid in urine | FJFS | 15 mg/L | NE |
| Trichloroethanol in blood (SH) | FJFS | 0.5 mg/L | NE | ||
| Xylenes | 9547-6 10642-3 10838-3 1330-27-7 | Methylhippuric acid in urine | FJ | 1.5 mg/g creat. | – |
*Indicators of excessive exposure (EE) are those that do not have diagnostic or clinical significance. They assess the absorption of agents through all exposure routes and, when altered—after ruling out other non-occupational causes that could justify the finding—indicate the possibility of exposure above occupational exposure limits. Samples should be collected during work shifts when the worker is actually exposed to the agent being monitored.
TABLE 2 – Biological Indicators of Exposure with Clinical Significance (IBE/SC)*
| Substance | CAS Number | Indicator(s) | Collection Time | IBE/EE Value | Remarks |
| Cadmium and its inorganic compounds | 7440-43-9 | Cadmium in urine | NC | 5 µg/g creat. | – |
| Lead and its inorganic compounds | 7439-92-1 | Lead in blood (Pb-S) | NC | 60 µg/100ml (M) | EPNE |
| Delta-Aminolevulinic Acid in urine (ALA-U) | NC | 10 mg/g creat. | EPNE, NE | ||
| Insecticides inhibiting cholinesterase | Erythrocyte acetylcholinesterase activity | FJ | 70% of baseline activity (#) | NE | |
| Butyrylcholinesterase activity in plasma or serum | FJ | 60% of baseline activity (#) | NE | ||
| Fluorine, hydrofluoric acid, and inorganic fluorides | Urinary fluoride | AJ48 | 2 mg/L | EPNE |
*Biological indicators with clinical significance (SC) show organic dysfunctions and adverse health effects.
(#) Baseline activity is the pre-occupational enzymatic activity and must be established with the employee away from exposure to cholinesterase-inhibiting insecticides for at least 30 (thirty) days. (M) Women of childbearing age with blood lead (Pb-S) levels of 30 µg/100ml or more must be removed from exposure to the agent.
Abbreviations:
- IBE/EE – Biological Indicators of Excessive Exposure
- IBE/SC – Biological Indicators of Exposure with Clinical Significance
- µg/g creat. – Micrograms per gram of creatinine
- µg/L – Micrograms per liter
- AJ – Before Shift
- AJ-FJ – Pre and post-shift difference
- AJ48 – Before shift with at least 48 hours without exposure
- AJFS – Start of the last work shift of the week
- EPNE – Found in non-occupationally exposed populations
- FJ – End of work shift
- FJFS – End of the last workday of the week
- FS – After 4 or 5 consecutive work shifts
- H – Analytical method requires hydrolysis for this IBE/EE
- SH – Analytical method must be performed without hydrolysis for this IBE/EE
- mg/L – Milligrams per liter
- NC – Non-critical (can be collected at any time as long as the worker has been working in recent weeks)
- NE – Non-specific (can be found from exposure to other substances)
- NF – Values for non-smokers (smokers have elevated baseline values of this indicator, making interpretation unfeasible)
- pmol/g hemog – Picomoles per gram of hemoglobin
- ppm – Parts per million