Medical Management Guidelines
for
Xylene
(C6H4)(CH3)2
CAS#:
1330-20-7
UN#
1307
Synonyms include dimethylbenzene, methyl toluene, xylol, and mixed xylenes.
- Persons exposed only to xylene vapor do not pose substantial risks of secondary contamination. Persons whose clothing or skin is contaminated with liquid xylene can cause secondary contamination by direct contact or through off-gassing vapor.
- Xylene is a clear, colorless liquid. It is volatile, readily producing flammable and toxic concentrations at room temperature. Its vapor is heavier than air and may accumulate in low-lying areas. Xylene's odor generally provides adequate warning of hazardous concentrations.
- Xylene is rapidly absorbed after inhalation and ingestion. Exposure via ingestion and inhalation produces systemic toxicity. Xylene is slowly absorbed through intact skin, but percutaneous absorption may contribute to total body burden.
Description
Xylene exists as three isomers (ortho-, meta-, and para-xylene), which can be found singly or, more commonly, mixed in varying proportions. Commercial grade xylene, in which m-xylene is usually the major constituent, is a clear, colorless liquid with a sweet, aromatic odor. It is generally referred to as Mixed, Total or Technical-Grade Xylene. There is a fourth structural isomer, ethylbenzene (C6H5)(C2H5) that may be present as a congener, but is not toxicologically distinct to a significant degree. Xylene is flammable at room temperature; therefore, it constitutes a fire hazard. It is insoluble in water, but mixes readily with many organic solvents. Xylene is less dense than water and will float on the surface of water.
Routes of Exposure
Inhalation
Most exposures to xylene occur by inhalation and xylene is readily absorbed from the lungs. Xylene's odor threshold is about 1 ppm, which is 100 times less than the OSHA PEL and generally provides adequate warning of acutely hazardous concentrations. Irritation of eye and throat occur at about 200 ppm. Xylene vapor is heavier than air and may cause asphyxiation in enclosed, poorly ventilated, or low-lying areas.
Children exposed to the same levels of xylene vapor as adults may receive a larger dose because they have greater lung surface area:body weight ratios and increased minute volumes:weight ratios. In addition, they may be exposed to higher levels than adults in the same location because of their short stature and the higher levels of xylene vapor found nearer to the ground.
Skin/Eye Contact
Xylene vapor is only mildly irritating to mucous membranes; however, xylene splashed in the eyes can result in corneal injury. Repeated or prolonged skin contact with liquid xylene can defat the skin, causing it to crack and peel. Percutaneous absorption is slow through intact skin; however, xylene absorbed through the skin may contribute to body burden.
Children are more vulnerable to toxicants absorbed through the skin because of their relatively larger surface area:body weight ratio.
Ingestion
Acute systemic toxicity can result from ingestion of xylene.
Sources/Uses
Xylene is among the 30 most abundantly produced chemicals in the United States. It is obtained primarily from crude petroleum. It is widely used as a degreasing agent and as a thinner and solvent in paints, inks, adhesives, and many other products. It is commonly found as a solvent in pesticide products.
Standards and Guidelines
OSHA PEL (permissible exposure limit) = 100 ppm (averaged over an 8-hour workshift) NIOSH IDLH (immediately dangerous to life or health) = 900 ppm
Physical PropertiesDescription: Clear, colorless liquid
Warning properties: Adequate; sweet, aromatic odor at 1 ppm
Molecular weight: 106.2 daltons
Boiling point (760 mm Hg)*: 292ºF (144ºC), 269ºF (139ºC), and 281ºF (138ºC)
Freezing point*: -13ºF (-25ºC), -54ºF (-48ºC), and 56ºF (13ºC)
Specific gravity*: 0.88, 0.86, and 0.86 (water = 1)
Vapor pressure*: 5, 6, and 6.5 mm Hg at 68ºF (20ºC)
Gas density: 3.8 (air = 1)
Water solubility: insoluble
Flammability*: 63ºF (17ºC), 81ºF (27ºC), 81ºF (27ºC)
Flammable range: 1.0% to 7.0% (concentration in air)
*ortho-, meta-, and para-xylene, respectively.
Incompatibilities
Xylene reacts with strong oxidizers and strong acids.
Health Effects
- Xylene is irritating to the skin, eyes, and respiratory tract. It can cause systemic toxicity by ingestion or inhalation. The most common route of exposure is via inhalation.
- Symptoms of xylene poisoning include CNS effects (headache, dizziness, ataxia, drowsiness, excitement, tremor, and coma), ventricular arrythmias, acute pulmonary edema, respiratory depression, nausea, vomiting, and reversible hepatic impairment.
- The mechanism by which xylene produces toxicity is not known.
Prehospital Management
Because manganese is a natural component of the environment, you are always exposed to low levels of it in water, air, soil, and food. In drinking water, levels are usually about 0.004 parts manganese per million parts (ppm) of water. In air, levels are usually about 0.00002 milligrams manganese per cubic meter (mg/m³) of air. Natural levels in soil usually range from 40 to 900 ppm. Manganese is also a normal part of living things, including both plants and animals, so it is present in foods. For nearly all people, food is the main source of manganese, and usual daily intakes range from about 1 to 10 mg/day. The exact amount you take in depends on your diet.
You are most likely to be exposed to higher-than-usual levels of manganese or manganese-containing chemicals if you work in a factory where manganese metal is produced from manganese ores or where manganese compounds are used to make steel or other products. In these factories you would be exposed mainly by breathing in manganese dust. If you live near such a factory you could also be exposed to higher-than-usual levels of manganese dust in the outside air, although the amounts would be much lower than in the factory. You might be exposed to higher-than-usual levels if you live near a coal- or oil-burning factory because manganese is released into the air when these fossil fuels are burned. Some areas of the country use a gasoline that has manganese added to it to increase performance. You could also be exposed to higher-than-usual levels of manganese if you live in a major urban area where such gasoline is used, if you have a job in which you make or have contact with that gasoline every day (such as a mechanic), or if you are exposed to a high amount of car exhaust on a daily basis (at bus stops, gas stations, etc.). You can also be exposed to manganese if you use pesticides that contain it. People who deal with such pesticides may be exposed through skin contact, but there have been instances in which workers may have accidentally eaten or inhaled some pesticides. You may also be exposed to manganese by eating foods that contain small, leftover amounts (residues) of these pesticides.
If manganese compounds, either naturally-occurring or from a factory or a hazardous waste site, get into water, you could be exposed to higher-than-usual levels by drinking the water.
See Chapter 5 of the toxicoloigcal profile for more information on how you might be exposed to manganese or its compounds.
Emergency Department Management
Humans are exposed to manganese in the food and water they eat and drink and in the air they breathe. Infants eat manganese that is present in breast milk, soy-based infant formulas, or cow’s milk. The amount of manganese in these sources is generally not a problem, and they provide the manganese that is necessary for normal functioning of the body. If you live near a hazardous waste site, you could possibly eat or drink higher-than usual levels of manganese that are in soil or water or breathe manganese-containing dust particles in the air that come from the waste site. The contribution of these exposure routes to manganese’s toxicity is uncertain; in general, adverse effects in people exposed through these routes have only been reported when environmental manganese levels were quite high. If you get manganese-contaminated soil or water on your skin, very little will enter your body, so this is not of concern. If you swallow manganese in water or in soil, most is excreted in the feces. However, about 3–5% is usually taken up and kept in the body. If you breathe air containing manganese dust, many of the smaller dust particles will be trapped in your lungs. Some of the manganese in these small particles may then dissolve in the lungs and enter the blood. The exact amount that may enter the blood is not known. Larger particles and those that do not dissolve will be coughed up, in a sticky layer of mucus, out of the lungs and into the throat, where they will be swallowed and will enter the stomach.
Manganese is a regular part of the human body; it is a necessary component in order for the body to work properly. The body normally controls the amount of absorbed manganese. For example, if large amounts of manganese are eaten in the diet, the body excretes large amounts in the feces. Therefore, the total amount of manganese in the body tends to stay about the same, even when exposure rates are higher or lower than usual. However, if too much manganese is taken in, the body may not be able to adjust for the added amount.
See Chapter 2 of the toxicological profile for more information on how manganese enters and leaves the body.
Patient Information Sheet
To protect the public from the harmful effects of toxic chemicals and to find ways to treat people who have been harmed, scientists use many tests.
One way to see if a chemical will hurt people is to learn how the chemical is absorbed, used, and released by the body; for some chemicals, animal testing may be necessary. Animal testing may also be used to identify health effects such as cancer or birth defects. Without laboratory animals, scientists would lose a basic method to get information needed to make wise decisions to protect public health. Scientists have the responsibility to treat research animals with care and compassion. Laws today protect the welfare of research animals, and scientists must comply with strict animal care guidelines.
Manganese is an essential nutrient, and eating a small amount of it each day is important to stay healthy. Manganese is present in many foods, including grains and cereals, and is found in high concentrations in many foods, such as tea. The amount of manganese in typical western diets (about 1–10 mg manganese per day) appears to be enough to meet daily needs. Human diets with too little manganese can lead to slowed blood clotting, skin problems, changes in hair color, lowered cholesterol levels, and other alterations in metabolism. In animals, eating too little manganese can interfere with normal growth, bone formation, and reproduction.
Too much manganese may also cause serious illness. Most manganese compounds seem to cause the same effects, although it is unknown whether exposure to different manganese compounds results in slight differences in adverse effects. Manganese miners or steel workers exposed to high levels of manganese dust in air may have mental and emotional disturbances, and their body movements may become slow and clumsy. This combination of symptoms is a disease called ‘manganism.’ Workers do not usually develop symptoms of manganism unless they have been exposed to manganese for many months or years. Manganism occurs because too much manganese injures a part of the brain that helps control body movements. Some of the symptoms of manganism may improve upon certain medical treatments, but the improvements are usually temporary, and the brain injury is permanent. Manganism has been reported most often in miners. It has only been reported a few times in other workers exposed to the metal, such as steel workers. The symptoms most commonly observed in occupational workers (other than miners) include difficulty in the following motor skills: holding one’s hand steady, performing fast hand movements, and maintaining balance when tested. These symptoms are not as severe as those related to manganism, indicating that the effects caused by manganese over-exposure are related to the level of exposure.
Most people who inhale manganese are involved in jobs where they are exposed to the metal. There is a possibility that people can be exposed to manganese in the air if they live near a plant that uses manganese, or if they live in a high traffic area and the automobiles burn manganese in the gasoline. A recent study showed that people who inhaled manganese from the air and who had high levels of manganese in their blood showed signs of neurological problems that were similar to those reported in occupationally-exposed persons. The neurological problems were most significant in the people aged 50 years and older.
It is not certain whether eating or drinking too much manganese can cause symptoms of manganism. In one report, people who drank water containing high concentrations of manganese developed a number of symptoms that were similar to those seen in manganese miners and steel workers. However, it is not clear whether these effects were caused by the manganese alone; other effects were noted, suggesting that other compounds may have been involved. In another report, people who drank water with above-average levels of manganese seemed to have a slightly higher frequency of symptoms such as weakness, stiff muscles, and trembling hands. However, these symptoms are not specific for manganism and might have been caused by other factors. Another study discovered that people who ate food with high concentrations of manganese, while also eating a diet low in magnesium, suffered nerve disease. Another study in adults over 40 years old who drank water with high manganese levels for at least 10 years reported no changes in behavior and no symptoms, that commonly occur in people exposed to excess levels of manganese. Two studies reported that children who drank water and who ate food with higher-than-usual levels of manganese did more poorly in school and on specific tests that measure coordination than children who had not eaten above-average amounts of manganese. However, these studies included several limitations; it is not clear whether the adverse effects in the children were caused only by eating too much manganese.
Studies in animals have shown that very high levels of manganese in food or water can cause changes in the brain. This information suggests that high levels of manganese in food or water might cause changes in the function of the nervous system. However, people exposed to manganese concentrations typically found in food, water, or air have little cause for concern.
Breathing too much manganese dust over a short or long time can cause irritation of the lungs. Sometimes this makes breathing difficult, and it can also increase the chances of getting a lung infection, such as pneumonia. However, this can happen from breathing in many kinds of dust particles and not just those that contain manganese.
A common effect in men who are exposed to high levels (levels seen in some occupational studies) of manganese dust in the air over a long time is impotence. Studies in animals show that too much manganese may also injure the testes. Much less is known about the effects of too much manganese on women’s ability to reproduce. Studies in animals suggest that too much manganese can negatively affect a female’s ability to reproduce.
No studies have been done to determine whether breathing manganese dust causes cancer in humans. Some studies in animals show that eating large amounts of manganese might increase the chances of getting cancer. However, only a few animals in these studies developed cancer, and it was difficult to tell whether the tumors were really caused by the excess manganese. Thus, there is little evidence to suggest that cancer is a major concern for people exposed to manganese in the environment or near hazardous waste sites. The EPA has determined that manganese is not classifiable as a human carcinogen.
One compound that contains manganese, potassium permanganate, damages the skin. Two other compounds that contain manganese, the pesticides maneb and mancozeb, can cause skin reactions in people who have allergies to these pesticides. Skin rashes can occur because of these allergies, but once the exposure to the pesticide is stopped, the rashes and any other effects will usually go away. However, once a person has developed an allergy to a particular manganese-containing pesticide, that person may have similar allergic reactions to different, but related, pesticides.
The negative adverse effects of exposure to excess levels of manganese have been observed in all ages. Several studies in humans and animals indicate that the elderly may be a potentially susceptible population to the adverse effects of manganese exposure. Further, studies show that the young may also be a susceptible population. Effects of exposure to high levels of manganese in children are discussed in Section 1.6.
Chapter 2 of the toxicological profile has more information on the health effects of manganese exposure in humans and animals.
Follow-up Instructions
Keep this page and take it with you to your next appointment. Follow only the instructions checked below.
Print instructions only.
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[ ] Call your doctor or the Emergency Department if you develop any unusual signs or symptoms within the next 24 hours, especially:
- coughing
- shortness of breath or wheezing
- chest pain or tightness
- increased pain or a discharge from exposed eyes
- increased redness or pain or a pus-like discharge in the area of a skin burn
- fever
[ ] No follow-up appointment is necessary unless you develop any of the symptoms listed above.
[ ] Call for an appointment with Dr.____ in the practice of ________.
When you call for your appointment, please say that you were treated in the Emergency Department at _________ Hospital by________and were advised to be seen again in ____days.
[ ] Return to the Emergency Department/Clinic on ____ (date) at _____ AM/PM for a follow-up examination.
[ ] Do not perform vigorous physical activities for 1 to 2 days.
[ ] You may resume everyday activities including driving and operating machinery.
[ ] Do not return to work for _____days.
[ ] You may return to work on a limited basis. See instructions below.
[ ] Avoid exposure to cigarette smoke for 72 hours; smoke may worsen the condition of your lungs.
[ ] Avoid drinking alcoholic beverages for at least 24 hours; alcohol may worsen injury to your stomach or have other effects.
[ ] Avoid taking the following medications: ________________
[ ] You may continue taking the following medication(s) that your doctor(s) prescribed for you: _______________________________
[ ] Other instructions: ____________________________________ _____________________________________________________
- Provide the Emergency Department with the name and the number of your primary care physician so that the ED can send him or her a record of your emergency department visit.
- You or your physician can get more information on the chemical by contacting: ____________ or _____________, or by checking out the following Internet Web sites: ___________;__________.
Signature of patient _______________ Date ____________
Signature of physician _____________ Date ____________
ATSDR can tell you where to find occupational and environmental health clinics. Their specialists can recognize, evaluate, and treat illnesses resulting from exposure to hazardous substances. You can also contact your community or state health or environmental quality department if you have any more questions or concerns.
For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Environmental Medicine
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-800-CDC-INFO • 888-232-6348 (TTY)
Email: cdcinfo@cdc.gov
