Toluene — biological monitoring
When to suspect: Paints / thinners, printing, adhesives, rubber, fuel, degreasing, footwear & leather.
Urine toluene / o-cresol; blood toluene (alternate) (mg/L · mg/g creat)
| Level | Interpretation |
|---|---|
| Urine toluene 0.03 | ACGIH BEI — end of shift (primary marker, mg/L) |
| o-Cresol 0.3 | ACGIH BEI — end of shift (mg/g creatinine, with hydrolysis) |
| Blood toluene 0.02 | ACGIH BEI — prior to last shift of workweek (mg/L) |
Urinary toluene is the primary/specific marker; o-cresol BEI overlaps smoker background. Hippuric acid was dropped as a BEI in 2010.
Biological exposure index
ACGIH BEI: urine toluene 0.03 mg/L (EOS); o-cresol 0.3 mg/g creatinine (EOS, hydrolysed); blood toluene 0.02 mg/L (prior to last shift).
Basis: ACGIH BEI; NIOSH NMAM 8321 (o-cresol).
Sample collection & preparation
- Urine: clean plastic → transport tube. Blood toluene: glass headspace/VOC tube, collected to exclude air (volatile — keep sealed).
- o-Cresol/urine toluene = END OF SHIFT; blood toluene = prior to last shift of the workweek.
- Avoid ambient solvent-vapour contamination. No fasting.
Statutory basis. Factories Act 1948 sets only AIR limits (Second Schedule TWA/STEL, s.41F) and mandates the hazardous-process exam (s.41C, ≤12-monthly); it gives NO blood/urine values. The ranges below are ACGIH BEI / OSHA / clinical benchmarks (India has not adopted biological limits into law).
Reference information for occupational-health professionals — not medical advice, and not a substitute for examination by a qualified physician.
All 27 agents — toxicology & biological monitoring
MedFactory — Occupational Health Centre software for Indian factories