I would like to consult the experts regarding the hazards of xylene.
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This post was last edited by lyhh9024 on 2010-10-13 07:57. Hello, I would like to ask whether xylene is harmful to the blood and carcinogenic. Because there is disagreement regarding p-xylene at the moment; some say it is carcinogenic while others say it is not. But it has a stimulating effect on nerves. I would like to ask whether it has a strong carcinogenic effect? Another question is regarding blended gasoline ； Blended gasoline mainly consists of materials such as cracked C9 hydrocarbons, C5 hydrocarbons, naphtha, and aromatics. Is it highly carcinogenic to the human body? Can it be understood in this way that the toxicity of the chemical components in gasoline depends on whether there is direct contact and on the duration of that contact? If there is no direct contact, and the duration of contact is no more than two years, or if the smell detected is very faint – basically undetectable – then wouldn’t the toxicity pose no risk of causing cancer in the body? My personal work experience is ； I worked as an accountant in an office about 50 meters away from the oil depot; over the course of a year, the company carried out procedures for exchanging and adjusting benzene. Two to three times a week. The oil depot is very small; it can hold at most 1,000 tons of gasoline. The process of blending and mixing benzene involves feeding the raw benzene directly into the tank through pipelines; after blending, it is then transported directly to tank trucks via pipelines. The entire process is carried out in a closed system, with the raw materials not being exposed to air. Due to factors such as pores, the odor is very pungent when adjusting benzene in summer, but it is barely noticeable at other times. Now, I work in an office about 100 meters away; there’s no odor, and I’ve never had direct contact with chemical raw materials either. Based on this work experience, what is the extent of the harm to the body caused by substances such as xylene, carbon nine, carbon five, and aromatics? This depends on the distance from these substances (about 50 meters per year; the smell is quite strong when mixing benzene, while other odors are only faintly detectable. Currently, the distance is around 100 meters, with almost no gasoline smell at all), as well as the level of exposure (working in an office, with no direct contact with the liquid raw materials). To what extent does this exposure pose a risk or have an impact on the health? Thank you! ! ! ! !
Reply to 1# cucwalnut: Health hazards: Xylene is irritating to the eyes and upper respiratory tract; at high concentrations, it has an **effect on the central nervous system. Acute poisoning: Inhaling high concentrations of this substance over a short period can cause significant irritation of the eyes and upper respiratory tract, congestion of the conjunctiva and pharynx, dizziness, headache, nausea, vomiting, chest tightness, weakness in the limbs, confusion, and unsteady gait. In severe cases, there may be restlessness, convulsions, or coma. Some have hysterical episodes. Chronic effects: Long-term exposure leads to neurasthenic syndrome; female workers experience menstrual irregularities, while workers often suffer from dry skin, chapping, and dermatitis. Routes of exposure: skin contact, eye contact, inhalation, ingestion. Long-term exposure is definitely bad for the body
Reply to 3# yy050811044: Hello, do you mean direct contact with liquids that contain chemical substances such as xylene? My work experience ； I worked as an accountant in an office about 50 meters away from the oil depot; over the course of a year, the company carried out procedures for exchanging and adjusting benzene. Two to three times a week. The oil depot is very small; it can hold at most 1,000 tons of gasoline. The process of blending and mixing benzene involves feeding the raw benzene directly into the tank through pipelines; after blending, it is then transported directly to tank trucks via pipelines. The entire process is carried out in a closed system, with the raw materials not being exposed to air. Due to factors such as pores, the odor is very pungent when adjusting benzene in summer, but it is barely noticeable at other times. Now, I work in an office about 100 meters away; there’s no odor, and I’ve never had direct contact with chemical raw materials either. Given the real circumstances of this experience, is it harmful to the body? Thank you!
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There are certainly risks, as it’s impossible to work in the chemical industry without facing any hazards. However, if you work in this field for a short period of time, the risk of developing cancer is not significant. Nutrition experts recommend that those who conduct chemical experiments eat more wood ear mushrooms to help detoxify the body; they also suggest drinking more milk.
There is definitely some absolute harm, but relatively speaking, the harm in your case can be completely ignored. It’s similar to the amount of pesticide residues on vegetables bought from the market.
Reply to 6# Yang Xue CCEUP: Hello, I am not a front-line worker in the chemical industry; I am an accountant in the office. Previously it was about 50 meters away from the oil depot; now it’s 100 meters. I’m in the office and don’t come into contact with gasoline raw materials. Before, there was a pungent smell when mixing benzene, and this happened two or three times a week, for a year. It has no taste now, and it’s not mixed with benzene either. Is it very harmful?
I have worked in aromatic compound plants for many years, and in xylene plants for four years, experiencing both the construction phase and operational phases. If you take proper precautions against the hazards of xylene, then the problem you mentioned is basically not a problem at all. Finally, the carcinogenicity of xylene or gasoline is a topic discussed by disease experts; otherwise we would have stopped producing them long ago.
Xylene is moderately toxic. After skin absorption, its impact on health is much smaller than that of benzene. If xylene or a solvent containing xylene is accidentally swallowed, it will severely irritate the esophagus and stomach, causing vomiting; it may also lead to hemopneumonia. In such cases, liquid paraffin should be drunk immediately, and medical attention should be sought promptly. The LC for xylene vapor in mice is 6000*10-6, and the lowest oral lethal dose in rats is 4000 mg/kg. Xylene is irritating to the eyes and upper respiratory tract; at high concentrations, it has an effect on the central nervous system. Acute poisoning: Inhaling high concentrations of this substance over a short period can cause significant irritation of the eyes and upper respiratory tract, congestion of the conjunctiva and throat, dizziness, headache, nausea, chest tightness, weakness in the limbs, confusion, and unsteady gait. In severe cases, there may be restlessness, convulsions, or coma. Some have hysterical episodes. Chronic effects: Prolonged exposure can lead to neurasthenia syndrome, and in women it may cause menstrual irregularities. Skin contact often leads to dry skin, chapping, and dermatitis. In occupational exposure, xylene enters the body primarily through the respiratory tract. For all the isomers of xylene, the absorption of their vapors by the lungs occurs in the same manner, accounting for 60% to 70% of the total amount; this level of absorption remains relatively constant throughout the entire period of exposure. Xylene solutions can be absorbed through intact skin at an average rate of 2.25 µg/(cm3·min) (range: 0.7–4.3 µg/(cm3·min)), while the transdermal absorption of xylene vapor is negligible compared to direct contact with the liquid. The residue and accumulation of xylene are not severe; as we have already mentioned, xylene that enters the body can be converted into formic acid in the presence of NADP (enzyme II) and NAD (enzyme I) in the body. This formic acid then combines with glycine to form methylmarboxylate, which is almost entirely excreted from the body within 18 hours. Even the 3%-6% of xylene that remains in the lungs after inhalation is completely exhaled within 3 hours after exposure (with a half-life of 0.5–1 hour). The test used to assess exposure to xylene involves measuring the level of methyl hippuric acid in urine; some also suggest measuring the amount of xylene in exhaled breath or blood, but the results from these latter methods are often inaccurate. Since methyl hippuric acid is not naturally present in urine, and since it constitutes almost all of the retained xylene metabolites, detecting its presence is the best confirmation of a xylene exposure test. Xylene can persist in drinking water for a considerable period of time. When the concentration of xylene in tap water is 5 mg/L, its odor intensity corresponds to level 5; the characteristic odor of xylene takes 7 to 8 days to disappear ； When the odor intensity is at level 3, it takes 4 to 5 days. The odor of xylene in river water persists for a short period, which is related to the initial concentration; it generally remains for 3 to 5 days. So, there is no harm in the situation you mentioned.
The last edit to this post was made by cucwalnut on 2010-10-13 00:28. Reply 9# lw*ou Hello, I have a question I’d like to ask； Throughout the process of producing blended gasoline, for personnel who are not part of the front-line staff, such as accountants and cafeteria workers, they generally work within a range of 50 to 100 meters from the fuel depot; at a distance of 50 meters, the smell of benzene used in blending gasoline is quite strong, and this occurs two or three times a week. One year. There’s no distinct smell at 100 meters, because the distance is so great – how much of the oil vapor remains at that distance? If no smell can be detected, it means that very little oil vapor has reached this area; therefore, the harm to the body is minimal due to the low concentration, as the distance from the oil depot is quite large. Is it possible that there are places where no odor can be detected, yet they still fail to meet safety standards and have a high carcinogenic potential? Generally, does any oil and gas that exceeds the safe concentration have an odor? This is because the various components in gasoline have odors of their own. Is it possible that the raw materials in gasoline have no odor of their own, so nothing can be smelled; and as a result, even strong toxic fumes might go unnoticed? Is this possible even for gasoline alone? In my work experience, is it possible for carcinogens to accumulate in the body and cause lesions? Is it necessary to test various components in gasoline in order to determine whether it is safe? If it has no odor, can it be said that it poses little harm to the human body and is safe? In our country, could there be a situation where the maximum concentration level is reached, yet no odor can be detected, even though it has already exceeded the **safety standards? (For the various components in gasoline) What confuses me now is that I can’t detect any odor, but since no measurements have been taken, I don’t know whether it poses a significant hazard. For gasoline, the absence of any odor can indicate that it hasn’t exceeded the **safety standards**, while a strong odor may suggest that the concentration has surpassed safe levels. Thank you! Thank you!