What is Tetrahydrofuran?

Tetrahydrofuran (also known as tetramethylene oxide) has the formula C₄H₈O. [1] It is a clear, colourless liquid with an ethereal odour. It is less dense than water, and its vapours are heavier than air. Tetrahydofuran is highly flammable and oxidises readily in air to form unstable peroxides that may explode spontaneously.

What is Tetrahydrofuran used for?

Tetrahydrofuran is used as a solvent and in various chemical processes, including:

• Polyvinyl Chloride & Vinyl Coatings: Used in coatings, adhesives, and inks.
• Reactions: Used in Grignard reactions and as an intermediate in chemical synthesis.
• Manufacturing: Makes products like adipic acid, motor fuels, vitamins, hormones, perfumes, insecticides, polytetramethylene ether glycol, and polyurethane elastomers.
• Food Packaging: utilised in materials for packaging, transport, and storage.

Sources & Routes of Exposure 

Source of Exposure

Workplace: Mainly through inhalation and skin contact where tetrahydrofuran is produced or used.

Routes of Exposure

Exposure to tetrahydrofuran can occur via:

• Inhalation
• Ingestion
• Eye Contact
• Skin Contact

Health Effects

Acute Effects

• Skin: Can cause dermatitis.
• Inhalation: Irritates eyes, nose, and throat; high levels affect CNS, causing headaches, dizziness, and fatigue.
• Oral Toxicity: Fatal doses estimated between 3,500-35,000 mg.

Chronic Effects

• Liver, kidney, CNS, respiratory: Effects seen in workers and animals exposed to high levels.
• Blood Chemistry: Changes noted in animal studies.

Carcinogenic Effects

• Unknown in Humans: No long-term human studies, but increases in kidney and liver tumours seen in animals.

Teratogenic/Reproductive Effects

• Developmental Delays: Seen in animals, with decreased body weight and developmental delays.

Safety

First Aid Measures

• Eye Contact: Flush with water for 15 minutes; seek medical attention.
• Skin Contact: Flush with water, remove contaminated clothing, and seek medical help.
• Inhalation: Move to fresh air, provide oxygen if needed, and seek medical help.
• Ingestion: Do NOT induce vomiting; seek medical help.

Exposure Controls & Personal Protection

• Personal Protection: Splash goggles, lab coat, gloves, and vapour respirator.
• Spill Protection: Full suit, respirator, and gloves.
• Hygiene: Wash hands and face thoroughly after handling; avoid eating, drinking, or smoking near Tetrahydrofuran.

Exposure Controls

Storage

Requirements: Store in a cool, dry, ventilated area in metal or amber glass containers.

Protection: Keep away from heat, sparks, and open flames. Use flame arrestors and nonsparking tools.

Precautions: Ground and bond containers to prevent static; handle containers with Tetrahydrofuran residues with care.

Spills & Leaks

• Safety: Keep unprotected individuals away.
• Procedure: Stop the leak if safe, remove ignition sources, ventilate the area, and use water spray to reduce vapours.
• Cleanup: Use sand or noncombustible material to absorb small spills. Contain large spills with dikes for disposal.

Regulation

United States

OSHA: The Occupational Safety & Health Administration has set the following Permissible Exposure Limit (PEL) for tetrahydrofuran:

• General Industry: 29 CFR 1910.1000 Z-1 Table -- 200 ppm, 590 mg/m3 TWA
• Construction Industry: 29 CFR 1926.55 Appendix A -- 200 ppm, 590 mg/m3 TWA
• Maritime: 29 CFR 1915.1000 Table Z-Shipyards -- 200 ppm, 590 mg/m3 TWA

ACGIH: American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) for tetrahydrofuran of 200 ppm, 590 mg/m3 TWA; 250 ppm, 737 mg/m3 STEL; BEI 

NIOSH: National Institute for Occupational Safety and Health has set a Recommended Exposure Limit (REL) for tetrahydofuran of 200 ppm, 590 mg/m3 TWA; 250 ppm, 735 mg/m3

Australia

Safe Work Australia: Safe Work Australia has established a Time Weighted Average Concentration (TWA) for tetrahydrofuran of 100ppm or 295mg/m3 for a 40-hour workweek.