SPEAKER 1: As a general service employee, you use a variety of chemicals or chemical products as part of your daily routine.
SPEAKER 2: Many of these substances are potentially hazardous to you and your coworkers. The actual risk you run using a particular chemical depends not only on the chemical but on the way you use it.
SPEAKER 1: With the proper handling, highly toxic or dangerous chemicals can be used safely. However, chemicals that are not highly toxic can be extremely hazardous if handled improperly.
SPEAKER 2: Even our food contains small doses of chemicals that, in high concentrations, are harmful. For example, tiny amounts of copper and iodine are found in many foods and are essential to proper health. Yet too much of either can poison you.
SPEAKER 1: This program presents some information about toxicology, the study of the harmful effects of chemicals on the body. This information will help you understand the hazardous chemicals that you encounter in your work. The program also recommends guidelines that will help you use all chemicals safely.
SPEAKER 2: Whether or not a chemical exposure results in injury depends on many factors. In addition to the dose, the outcome of exposure is determined by the way the chemical enters the body, the properties of the chemical, and the susceptibility of the person receiving the dose. Let's look at these factors in more detail.
SPEAKER 3: How do toxic substances get into our bodies?
SPEAKER 1: Let's begin by talking about the primary routes of entry for toxic substances. No chemical can harm you until it has actually touched or entered your body. Chemicals can enter the body through the mouth, the lungs, the eyes, and the skin.
To protect yourself, keep all chemicals, solids, liquids, and gases, off your skin and away from your eyes. Avoid breathing vapors and dusts. Don't let chemicals contaminate your food. Wash your hands before eating and store and eat food away from your work area. Ingesting chemicals by accident may seem unlikely at work, but it can happen.
Cigarette smoke can increase the effects of indoor air pollutants and chemical vapors. So breathing smoke while working with chemicals is especially hazardous. The respiratory system is the most common route for gases, vapors, and small particulates to enter the body.
The lungs have a very large surface area so that oxygen can get into the blood. Unfortunately, this large surface area allows other gases and vapors to enter the body as well. Aerosols, mists, dusts, fumes, fogs, and microorganisms may be inhaled and deposited in the nose, throat and lungs.
Odors and irritant properties provide useful early warnings of overexposure. Chemicals such as ammonia are so irritating to the eyes and lungs that a person could never unknowingly receive a large dose. On the other hand, carbon monoxide and other odorless gases can be especially dangerous because they give you no warning at all when you are being poisoned.
Watch for symptoms of exposure to irritating gases or vapors. These include headache, irritation of eyes, nose, and throat, and increased secretion of mucus in the nose and throat. Exposure to some substances, including many common solvents, can cause narcotic effects. Symptoms include headache, confusion, dizziness, and, in extreme cases, unconsciousness or collapse. If you experience these symptoms, immediately reduce your exposure by increasing ventilation, closing containers, opening windows, or leaving the area. If your symptoms persist, get medical attention.
You may need to use a respirator for protection. If you do, be sure your equipment is selected by a qualified person. A proper fit is essential. Special respirators are needed to filter out chemical fumes.
The eyes are especially sensitive to chemicals. Most chemicals are irritating when splashed into the eyes and many cause painful burns or blindness. This custodian splashed a cleaning agent containing ammonia into an eye. They eye was still reddened and painful several weeks after the injury.
Don't rub your eyes if a foreign substance does get into them. Instead, wash your eyes in running water for at least 15 minutes, making sure to flush the whole eye surface. Use any available source of water such as a faucet or a water fountain.
Some people believe that if you have no cuts or open wounds, your skin protects you from poisons. That's not necessarily true. Several reactions can occur when a chemical comes in contact with your skin.
The skin may act as an effective barrier against chemical injury or penetration. Or the chemical may react with skin surfaces and cause local irritation such as redness, blisters, dryness, or chemical burns. In some people, a chemical in contact with the skin can cause an allergic or sensitivity reaction. After a person has been sensitized, even a small amount of the chemical can cause a rash or other reaction.
Certain chemicals may penetrate the skin and enter the blood stream. If your skin comes in contact with these chemicals for prolonged periods, they can build up in your system and make you ill. Therefore, you should do your best to keep the chemicals you work with away from your skin.
The health of the skin and the properties of the chemicals involved affect the way chemical substances penetrate the skin. Injured or diseased skin will offer less resistance to chemicals. Learn to recognize the early symptoms of skin exposure to chemicals. Watch for dry, whitened skin or redness and swelling. Other symptoms include rash, blisters, and itching.
It is extremely important to use gloves and other protective equipment to reduce the possibility of skin exposure to corrosive chemicals. Be sure to use the right kind of gloves for the chemicals you are using. A maintenance worker was filling a cooling line when some freon squirted on his hand. Although freon is not very toxic, it can cause freezing burns when it is under pressure.
A dairy farmer was cleaning his milking equipment when some lye spilled on his leg and shoe. Lye burns do not always hurt right away so he did not wash it off immediately. To reduce possible damage, wash any spilled lye off your skin, even if it does not seem painful.
Any time you get a chemical on your skin, rinse the affected area promptly and thoroughly using lots and lots of water. Use any available water supply. Remember, first aid for skin exposure to chemicals is washing with water, then seek medical attention.
SPEAKER 3: How much of a chemical can I be exposed to before it causes problems?
SPEAKER 2: For every chemical, even the least toxic, a large enough dose causes damage to health. For every chemical, even the most toxic, a small enough dose causes no damage to health. The dose is the amount of the chemical absorbed by the body. The dose depends on how much of the chemical is present as well as how long and how frequent the exposures are.
When talking about chemical exposures, it's useful to distinguish between acute and chronic toxicity. Acute toxicity is the potential for a chemical to cause harm after a single short exposure. Short exposure is commonly thought of as a single oral intake, a single contact with the skin or eyes, or a single exposure to contaminated air lasting less than a day.
Harmful health effects caused by acute exposure usually appear quickly. Burns from a cleaning agent or being overcome by chemical vapors are examples of the effects of acute exposure. Effects of acute exposure are often reversible. The effects disappear soon after the exposure ends.
Any injuries usually heal rapidly and recovery is complete. Exposure to some vapors may cause throat and eye irritation. But this stops soon after the vapors are removed.
Chronic toxicity is the potential of a chemical to cause harm following repeated exposure over a period of time. The pattern of exposure is usually regular or frequent exposure over a period of weeks, months, or years. Health effects caused by chronic exposure usually take some time to appear and they may not be recognized until they have reached advanced stages. By this time, permanent damage may have occurred.
A person who drinks alcohol every day may not show any signs of illness immediately. But long-term exposure can result in liver damage. Many, but not all, chronic effects of toxic substances are not reversible. They do not disappear once exposure stops.
Cigarette smoking can lead to lung cancer. But the risk of cancer declines once a person stops smoking. Once a person has cancer, however, the disease does not go away without treatment, even if the person quits smoking.
Chemical substances may have a broad range of toxic effects on an organism. Many substances produce their most important effects at specific sites called target sites. One chemical might affect the kidneys while another might affect the nervous system.
SPEAKER 3: So far, you've been talking about how chemicals get into the body and what can happen once they get there. I see that there's really no definite boundary between safe and unsafe exposure. Do all people react the same way to chemicals?
SPEAKER 1: Stating the danger presented by a chemical to humans or other animals is complicated. Because, within a given population, individuals may respond differently to the same dose of a chemical agent. At a certain dose of a chemical, some individuals show no reactions. A few react very strongly. The majority of individuals, however, fall in the range between the two extremes.
These differences in response are known as individual variation or susceptibility. The differences are often due to general health, heredity, diet, age, and sex. Let's look at some examples.
Some people are allergic to pollen or cat hair. But you can also be allergic to a chemical. Over time, exposure to some chemicals can lead to the development of an allergic skin rash or other reaction. The reaction flares up with further exposure to even small amounts of the chemical but goes away when exposure stops. This is called sensitisation. Epoxy resins and some solvents are common sensitizers.
Allergic reactions are often minor but they can be life-threatening. A person who is allergic to bee stings can suffer a fatal reaction following an insect sting that most people would regard as a minor nuisance. Some medical conditions may make some people more susceptible to the effects of certain chemicals. Heart or lung disease may make a person more susceptible to respiratory hazards while liver disease may limit the body's ability to get rid of chemicals.
Lifestyle is also important. Smoking, drinking, and nutritional habits can alter the effects of many chemicals. Developing fetuses are particularly sensitive to some substances. Although many people erroneously think the placenta protects the fetus from drugs and chemicals, the placenta is not a barrier to foreign compounds. It acts more like a sieve.
If a pregnant woman drinks too much alcohol, her baby is likely to have fetal alcohol syndrome. The baby may be retarded and deformed. Chemical damage to a fetus is most likely during the first 12 weeks of pregnancy, which includes a period when a woman may not know she is pregnant. During this time, the fetus's organs are forming and one small error caused by chemical damage can have a very large effect. Pregnant women or women planning pregnancy should take special care to avoid contact with chemicals at work and at home.
Only a very few chemicals have been shown to have reproductive effects in men. Nevertheless, it is a good idea for men to be careful when working with potentially dangerous chemicals. Men should avoid bringing chemically contaminated clothing into their homes where other family members might be exposed to it.
Only you know exactly how you handle chemicals and what special circumstances affect your susceptibility to poisoning. Find out about the health hazards of chemicals you work with so that you can better judge what protection you need.
SPEAKER 4: Aren't there standards or regulations that limit the amount of exposure a person can have?
SPEAKER 2: The federal government has set standards for exposure to several hundred hazardous chemicals. These standards represent levels of chemicals at which it is believed workers can be exposed for many years without harm. Because of individual variation and the uncertainties of toxicity ratings, these standards do not describe levels of exposure that are completely risk-free for all workers. They represent best estimates of safe exposure for the average healthy worker.
You can find out about the exposure standards, the properties and the hazards of chemicals, and safe handling procedures from material safety data sheets. Chemical manufacturers are required by law to provide customers with these sheets on request.
SPEAKER 1: Chemicals are used not only at work but in almost every aspect of our lives, even in protecting and preserving food. The use of toxic chemicals is a dilemma faced not only by laboratory and chemical workers but by everyone.
SPEAKER 2: Estimating the hazard posed by the use of a particular chemical is controversial and complex. It involves considering the way the chemical is used in addition to its toxicity.
SPEAKER 1: By learning about the potential hazards of the substances you use and by practicing appropriate procedures for those substances, you can safely work in an informed and intelligent manner.
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This program is designed as a guide for chemical safety in the workplace for general service workers. It was written and produced in 1985 by Jeanne A. Appling, Ph.D. Toxicologist for Cornell's Institute for Comparative & Environmental Toxicology, Judith A. Crawford, C.I.H., and Judith A. Goodloe, Ph.D. in partnership with the ETV Center, Media Services at Cornell University.