A paint thinner is a solvent used to thin oil-based paints. Solvents labeled "paint thinner" are usually mineral spirits having a flash point at about 40 °C (104 °F),^[1] the same as some popular brands of charcoal starter.^[2]

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Common solvents historically used as paint thinners include:^[3]

• Mineral spirits (North America) / White spirit (United Kingdom and Ireland)
• Acetone
• Turpentine
• Naphtha
• Toluene
• Lacquer thinner
• Methyl ethyl ketone (MEK)
• Dimethylformamide (DMF)
• Glycol ethers, such as 2-Butoxyethanol

Less common solvents used as paint thinner include:^{[4][failed verification]}

• Ethylbenzene
• Xylene
• n-Butyl acetate
• Butanol

Exposure to vapors created by paint containing thinner or its cleanup may be hazardous. The American Conference of Governmental Industrial Hygienists has established threshold limit values (TLVs) for most of these compounds.^{[citation needed]} TLV is defined as the maximum concentration in air which can be breathed by a normal person (i.e., excluding children, pregnant women, etc.) in the course of 40 hours per week (a typical American work week), day after day through their work life without long-term ill effects.

In underdeveloped countries, workers commonly experience much higher exposure to these chemicals with consequent damage to their health.^{[original research?]}

• Environmental impact of paint
• Substance-induced psychosis