Paraffin wax, also known as crystalline wax, is a substance that dissolves in non-polar solvents like gasoline, carbon disulfide, xylene, ether, benzene, chloroform, tetrachloride, and naphtha, but is insoluble in polar solvents such as water and methanol. Its main components are hydrocarbons with carbon atom numbers ranging from 18 to 30, with about 80% to 95% being straight-chain alkanes, and a small percentage of branched alkanes and single-ring cycloalkanes with long side chains (totaling less than 20%). Paraffin wax is generally produced from the distillation of crude oil lubricating oil fractions through solvent refining, solvent dewaxing, or cold crystallization and pressing dewaxing processes. After deoiling and further refining, it forms into flaky or needle-like crystals. Based on its degree of refinement, paraffin wax can be classified into fully refined, semi-refined, and crude paraffin wax.
Paraffin wax fumes may cause irritation to the eyes, skin, and respiratory system, leading to discomfort and nausea. High exposure or inhalation of paraffin wax fumes may result in irritation to the eyes, nose, and throat, accompanied by symptoms such as headaches, nausea, and dizziness. M. Enamul Hossain et al. have reported the potential health hazards of paraffin wax:
In occupational environments, paraffin wax may enter the body through inhalation, skin contact, and eye contact, posing health risks to workers. According to the National Institute for Occupational Safety and Health (NIOSH), the recommended exposure limit (REL) for paraffin wax fumes is set at 2 mg/m3, over an 8-hour workday.
Paraffin wax has been unfairly accused of being a carcinogen. Some writers claim that paraffin wax workers develop bladder cancer, while others suggest that scrotal cancer may result from such work. British writers sometimes use the term paraffin wax to refer to paraffin oil, which may indeed have carcinogenic properties. However, the name paraffin wax should be reserved for the chemical entity C27H66. When investigating unrefined, contaminated, oily, or acidic paraffin wax materials, it should be explicitly stated, as oily, dirty clothing and a complete lack of personal hygiene can lead to skin diseases.
In experimental work, Leitch and Kennaway found that many types of petroleum do not cause cancer. They heated non-carcinogenic California petroleum to 880°C, producing many aromatic compounds that were not present in the original petroleum and were carcinogenic. California petroleum is asphalt-based, while Appalachian petroleum is paraffin wax-based. In experiments with tar cancer in mice, Kennaway found that the highest cancer-producing tars contained very little paraffin wax, while tars with the most paraffin wax did not produce experimental cancer. Leitch reported that 30 out of 74 mice survived and developed tumors after frequent use of crude shale oil containing paraffin wax. However, Mook and Wander noted that injecting paraffin wax into human subcutaneous tissue once could cause tumors to form. Burrows and Jorstad wrote that paraffin wax, liquid vaseline, coal tar, and vegetable and animal oils form capsules (as do all foreign bodies) and fleshy lumps when they enter tissue. They believed these lipid solvents induce cancer, although malnutrition is the primary factor in cancer development, which has never been confirmed. Weidmann claimed that tumors caused by the injection of oils, liquid vaseline, or paraffin wax were not tumors but disfiguring foreign body granulomas.
As a byproduct of petroleum processing, paraffin wax releases harmful substances like benzene and toluene when burned. These substances not only irritate the respiratory system, but are also closely associated with the development of various respiratory diseases and even cancer. Long-term exposure to such environments poses a serious threat to human health. Here is an image of paraffin wax candles:
As a petroleum-derived product, the use of paraffin wax in skincare has been widespread, but its safety remains controversial. Studies suggest that paraffin wax may contain residual polycyclic aromatic hydrocarbons, which are carcinogenic and could pose a potential risk to skin health with long-term use. However, regulatory bodies like the FDA have taken steps to ensure that harmful impurities are minimized during the refining process. Additionally, the thick oil film formed by paraffin wax may temporarily retain skin moisture but could also clog pores, potentially exacerbating skin problems.
Scott conducted routine checks on all workers in the paraffin wax division of the Scottish shale oil industry over four years and found that half of the workers developed various skin lesions. These appeared a few weeks after starting work, persisted throughout employment, and disappeared upon termination of employment. Lesions included erythema, acne, papules, and pustules. He claimed that if a person worked in the paraffin wax industry for over twenty years, warts might develop into epitheliomas. He listed cases of epithelioma treated at the Royal Hospital between 1900 and 1921, showing that paraffin wax workers had the following case distribution: arms and hands 63%, face 16%, scrotum 16%, and groin 5%. White noted no evidence of skin disease among paraffin wax candle makers. White found that women and girls who worked year after year, covered in pure refined paraffin wax, were not harmed by the wax.
Food-grade paraffin wax is typically composed of high-purity long-chain alkanes, with extremely high chemical stability. It is widely used in various stages of food processing. For example, paraffin wax coatings effectively delay moisture evaporation, preserving the freshness of fruits and vegetables. In candy making, paraffin wax coatings give the candy a smooth, glossy surface and improve texture.
Food-grade paraffin wax undergoes strict purification processes to achieve high purity and is almost insoluble in water. It is edible and serves both functional and aesthetic purposes in food. Regulatory bodies like the FDA have approved paraffin wax as a food additive. However, it is important to note that while paraffin wax itself is not toxic, excessive ingestion of any substance may have adverse effects on the body. Therefore, food manufacturers must strictly follow national standards to control the use of paraffin wax.
General advice: Consult a doctor. Show the safety data sheet to the attending physician.
If inhaled: Move the person to fresh air. If breathing stops, perform artificial respiration. Consult a doctor.
If skin contact: Wash with soap and plenty of water. Consult a doctor.
If eye contact: Rinse thoroughly with plenty of water for at least 15 minutes and consult a doctor.
If swallowed: Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a doctor.
Precautions for safe handling: Avoid contact with skin and eyes. Avoid dust and aerosol formation. Avoid exposure—obtain special instructions before use. Provide appropriate exhaust ventilation at places where dust is formed.
Conditions for safe storage, including any incompatibilities: Store in a cool place. Keep the container tightly closed in a dry and well-ventilated place.
[1]https://en.wikipedia.org/wiki/Paraffin_wax
[2]https://www.britannica.com/science/paraffin-wax
[3]https://pubchem.ncbi.nlm.nih.gov/substance/482588360
[4]https://www.cdc.gov/niosh/npg/npgd0477.html
[5]https://www.sciencedirect.com/topics/chemical-engineering/paraffin-wax
[6]Wood, H B. Paraffin not productive of cancer[J]. The Journal of Cancer Research, 1929, 13(1): 97-102.
[7]https://baike.baidu.com/item/%E7%9F%B3%E8%9C%A1
[8]https://aacrjournals.org/jcancerres/article/13/1/97/449790/Paraffin-Not-Productive-of-Cancer
[9]http://www.vikit.cn/msds/8002-74-2.html
[10]Hossain M E, Khan M I, Ketata C, et al. Comparative pathway analysis of paraffin wax and beeswax for industrial applications[J]. International Journal of Characterization and Development of Novel Materials, 2010, 1(4): 1-13.
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