All chemicals have toxic effects at some dose level for some route of exposure. It is therefore wise to minimize exposure to chemicals. Chemicals can have local or systemic effects. Local toxicity refers to the direct action of chemicals at the point of contact. Systemic toxicity occurs when the chemical agent is absorbed into the bloodstream and distributed throughout the body, affecting one or more organs. Toxic effects are also classified as acute or chronic. Acute effects are observed shortly after exposure. Chronic effects result from long term exposures or appear after a latency period.
Dermal Contact: One of the most frequent exposures to chemicals is by contact with the skin. Spills and splashes can result in overt contamination of the skin. A common result of skin contact is localized irritation or burns. However, some materials are also absorbed through the skin to produce systemic poisoning. Skin contact hazards are often associated with caustic or acidic cleaners which are highly corrosive to skin tissue on contact or with petroleum based products which are irritating on repeated contact.
Inhalation: Inhalation of toxic vapors, mists, gases, or dusts can produce poisoning by absorption through the mucous membrane of the mouth, throat, and lungs and can seriously damage these tissues by local action. Inhaled gases or vapors may pass rapidly into the capillaries of the lungs and be carried into the circulatory system. The degree of injury resulting from inhalation of toxic substances depends on the toxicity of the material, its solubility in tissue fluids, its concentration, and the duration of exposure.
Inhalation hazards are most often associated with gases and volatile products such as adhesives, wood finishes, or paint thinners. Dust and non volatile liquids can also present an inhalation hazard. Materials in the form of dusts and particulates can become airborne when transferred from one container to another or by grinding and crushing. Splashes created from spills and during vigorous shaking and mixing also result in aerosol formation. Many of the particulates generated during such procedures do not settle out but remain suspended in the air and are carried about by air currents in the room. Some of these particulates are capable of being inhaled and deposited in the respiratory tract. For many operations it is not obvious that an aerosol is being generated and personnel may not be aware that a hazardous situation exists.
Ingestion: Ingestion of toxic materials can occur when contaminated hands come in contact with the mouth or with food items which are placed in the mouth. Food items and utensils themselves can become contaminated when stored near chemicals.
Ocular: The eyes are of particular concern because they are so sensitive to irritants. Ocular exposure can occur via splash or when contaminated hands rub the eyes. Few substances are innocuous in contact with the eyes and a considerable number are capable of causing burns and loss of vision. The eyes are very vascular and provide for rapid absorption of many chemicals.
IF ADEQUATE VENTILATION IS NOT IN PLACE A SERIOUS HEALTH HAZARD OR EXPLOSION HAZARD MAY BE CREATED.
Planning and implementation of control practices for the prevention of occupationally acquired cancer and protection of the general environment is to be included in all research programs and work involving known or suspected chemical carcinogens.
Definition: Chemical carcinogens are chemicals which have been demonstrated to cause a malignant disease, an increased incidence of cancer by the appearance of tumors at an earlier time than would be otherwise expected, or by promotion of tumors initiated from exposure to other chemicals.
OSHA currently regulates twenty-three chemical carcinogens, some of which may exist at WCU. Furthermore, the OSHA Research Division has listed in The Registry of Toxic Effects of Chemical Substances more than 2000 substances for which there is allegedly some degree of evidence of tumorigenicity or carcinogenicity and will be subject to future regulation.
Some potential carcinogens found in research laboratories will not be included in these lists because they are not ordinarily found in the industrial workplace or because there may not have been sufficient carcinogenicity testing to date. The faculty member is responsible for knowing the available information relating to the hazard potential for the chemicals used in his/her laboratory and should exercise judgment, in consultation with the Safety Office, as to the appropriate safety precautions which should be followed.
A designated work area must be established with restricted access to personnel who are aware of the hazards of the substances in use and the precautions necessary for safe handling and storage. The designated area may be the entire laboratory or a device such as a laboratory fume hood.
A foot or elbow operated hand wash facility should be available within the work area and a shower facility should also be located within easy access.
The exhaust ventilation system should maintain an inflow of air from the unregulated area into the work area. The exhaust air from the work area must be discharged directly to the outdoors clear of occupied buildings and air intakes. No re-circulation of exhaust air from the work area is permitted. The exhaust air from glove boxes should be treated by HEPA and charcoal filtration. Exhaust air treatment systems that remove chemical carcinogens from the exhaust air by collection mechanism such as filtration or absorption should be operated in a manner that permits maintenance so as to avoid direct contact with the collection medium. The need for and type of treatment for other primary containment equipment should be determined by the Safety Office.
Protective clothing such as a full-fastened laboratory coat or a disposable jumpsuit is to be worn in any area in which chemical carcinogens are being used. Clean clothing is to be provided weekly and should not be worn outside of the work area. Clothing contaminated by chemical carcinogens is to be decontaminated or disposed of immediately after an obvious exposure. Contaminated clothing must not be sent to the laundry until decontaminated. Gloves must be worn when handling chemical carcinogens. The practice of double gloving when handling chemical carcinogens is recommended. Disposable gloves are to be discarded after each use and immediately after known contact with a chemical carcinogen.
Work Area Identification
Entrances to all work areas, where chemical carcinogens are being used or stored, must be posted with signs bearing the legend: CAUTION - CHEMICAL CARCINOGEN Authorized Personnel Only.
Primary Containment Equipment
Procedures involving volatile chemical carcinogens and those involving solid or liquid chemical carcinogens that may result in the generation of aerosols must be conducted in a chemical fume hood, a biological safety cabinet, a glove box, or other suitable containment equipment. Examples of aerosol producing procedures are: the opening of closed vessels; transfer operations; weighing preparation of feed mixtures; and the application, injection, or incubation of a chemical carcinogen into experimental animals. Class II, type B biological safety cabinets are suitable for the conduct of tissue culture and other biological procedures involving chemical carcinogens. The faculty member should obtain guidance from the Safety Office on the selection and use of Class II biological safety cabinets. Primary containment equipment used for chemical carcinogens must display a label bearing the legend: CAUTION CHEMICAL CARCINOGEN.
Analytical instruments, when used with chemical carcinogens, are to be placed entirely within a chemical fume hood. When this is impossible, vapors or aerosols produced by these instruments should be captured through local exhaust ventilation at the site of their production. When a sample is removed from the analytical instrument, it should be placed in a tightly stoppered sample tube or otherwise safeguarded from contaminating the laboratory. Analytical equipment that becomes contaminated should not be used until it has been completely decontaminated.
Storage, Inventory and Identification
Stock quantities of chemical carcinogens are to be stored in designated storage areas. An inventory of stock quantities is to be maintained by the faculty member, who should provide copies to the Safety Office. The inventory records should include the quantities of chemical carcinogens acquired and dates of acquisition and disposition. Quantities of chemical carcinogens present in the work area should be kept to a minimum.
Storage vessels containing chemical carcinogens are to be first placed in an unbreakable outer container before being transported to laboratory work areas. Contaminated materials, which are transferred from work areas to disposal areas, must first be placed in a closed plastic bag or other suitable impermeable and sealed primary container. The primary container must be placed in a durable outer container before being transported.
Each vacuum service, including water aspirators, is to be protected with an absorbent or liquid trap and a HEPA filter to prevent entry of any chemical carcinogen into the system. When using a volatile carcinogen, a separate vacuum pump or other device placed in an appropriate chemical fume hood should be used.
The storage areas, stock containers and working solutions, and transport containers should have signs bearing the legend: CAUTION - CHEMICAL CARCINOGEN Authorized Personnel Only.
Chemical carcinogens are to be packaged to withstand shocks pressure changes, and any other condition, which might cause leakage of contents incident to ordinary handling during transportation. Shipments are to be in accordance with DOT regulations and must be coordinated through the Safety Office.
Decontamination and Disposal
Contaminated materials must either be decontaminated by procedures that decompose the chemical carcinogen, or be removed for subsequent disposal. Chemical carcinogens, which have spilled out of a primary container so as to constitute a hazard, must be inactivated in situ or should be absorbed by appropriate means for subsequent disposal. A means for assuring adequacy of clean up should be provided, for instance wipe tests or fluorescence tests.
Animal care personnel are to wear a completely closed jumpsuit or a complete clothing change and laboratory issue shoes or booties, head cover, and gloves. Clean clothing should be provided daily. Animal care personnel engaged in procedures where exposure to airborne particles contaminated with chemical carcinogens could occur must wear an appropriate face mask or respirator. The selection and use of an appropriate face mask or respirator is to be approved by the Safety Office. The face mask or respirator is not to be worn outside of the animal room. Used filters should be disposed of and the respirator housing should be decontaminated daily. Personnel should shower after completion of procedures that may result in the creation of airborne contamination in the animal room. Experimental animals are to be housed in cage systems that confine feed, feces, urine, and bedding within the enclosure. When using a volatile chemical carcinogen, the cage must be used in conjunction with appropriate ventilation systems. Alternative animal housing methods must be approved by the Safety Office.
Medical examinations are to be completed for employees who develop signs or symptoms associated with a hazardous chemical or whenever there is reason to believe that the employee has been exposed to a substance above OSHA limits.