Which two solvents are identified as toxic?

• A. Xylene and Tetrahydrofuran
• B. Xylene and Toluene
• C. Toluene and Cedarwood oil
• D. Xylene and Chloroform

Answer: (A)

Toxicity risk is a key factor in choosing and handling solvents in the lab. Xylene and tetrahydrofuran are the two solvents that are identified as toxic in the safety references used for histology practice. Xylene is a volatile aromatic solvent known to irritate skin, eyes, and the respiratory system and can affect the nervous system with exposure. Tetrahydrofuran is also toxic and highly flammable; it can be absorbed through the skin and inhaled, and it has the added risk of forming explosive peroxides if aged or exposed to air. Because these two are the ones flagged as toxic in the standard safety guidance, they’re the correct pairing. The other options involve solvents that, in the same safety context, are not identified together as toxic in that resource, or carry different hazard profiles that aren’t being highlighted in this specific question.