The degree to which a chemical exposure adversely affects the human body is contingent upon the dose of the chemical; the duration of the exposure; and the route in which the chemical entered the body. The minimization of exposure to hazardous chemicals must be a priority of all laboratory personnel. This section discusses the primary "Routes-of-Entry" (inhalation, ingestion, absorption, and injection) and certain methods for controlling the chemical hazards.
The following are brief descriptions of common causes of laboratory related incidents. Unexpected and possibly dangerous situations can result from one or more of the following:
Incorrect chemical handling
Incorrect amounts of
Incorrect order of
rate of addition of
two or more substances
Incorrect dilution of
using one or more
using expired chemicals
DO NOT INHALE VAPORS.
Experiments that generate vapors should be performed in a fumehood if at all possible. When fumehoods are not available some mechanism to remove vapors should be in place.
8.2 INGESTION EXPOSURE
Lab windows and doors should be kept closed at all times so that fumehoods work properly.
Large objects should not be placed in fumehoods. Fumehoods should only be used to temporary hold equipment and chemicals.
Never pipette by mouth! Use a pipette bulb.
No eating, drinking, or application of cosmetics is allowed in any lab.
Never use chemical equipment as containers for food or drink.
All tobacco products are PROHIBITED in or around any lab!
Never taste, nor deliberately inhale any laboratory chemical. Exception: special experiments may involve odors of non-hazardous substances.8.3 ABSORPTION EXPOSURE
Wear appropriate PPE for the procedure.
Conduct procedures so as to avoid splashes and spills.
IMMEDIATELY wash any splashed
chemical from your skin.
Most exposures from injections are caused by improper handling of needles and broken glassware. Laboratories using needles must have a proper disposal container for needles. Used needles will not be placed in the trash or any other unapproved container. Individuals should use prudent care when handling needles and other sharp objects.
Laboratories should also have an approved container for the disposal of broken glass. Scoops and hand brooms must be available to safely clean the area of broken glass.8.5 CHEMICAL HAZARD CLASS
Chemicals are categorized according to their hazard class. There are four main classes for chemical hazards. The following are simplistic definitions of the chemical hazard classes:
Flammable- Any material which has a flashpoint of < 100o F / 37.78 o C and burns in air, whether gas,
liquid, or solid. A flammable gas when mixed with air can explode if exposed to an ignition source.
Corrosive - Any material which will attack and irreversibly damage human tissues,
such as eyes, skin or mucous membranes, as well as other substances such as metal.
Poison (Toxic) - The ability of a substance in small quantities to cause severe or fatal
injuries by inhalation, absorption, or ingestion.
Reactive - A chemical substance or mixture that may vigorously polymerize, decompose, condense, or become self-reactive under conditions of shock, pressure or temperature. Examples of reactive materials are as follows:
8.6 HAZARD CLASS RATINGS
Chemical hazards are communicated through container labels. The most common types of hazard labels are the NFPA 704 Diamond and the HMIS Label.
The NFPA 704 (National Fire Protection Association) is a diamond-shaped label with colors, numbers and symbols to communicate chemical hazard information. The HMIS label (Hazardous Material Information System) is similar to the NFPAs system in which the differences between the two labels is that the HMIS label is rectangular in shape and also utilizes symbols indicating the PPE to be worn while working with the chemical.
8.7 RADIATION HAZARDS
The university is governed by a license issued by the State of Texas, Bureau of Radiation Control. Programs using radioactive material must do so in accordance with the universitys license. The following are general procedures to be followed while using radioactive materials.
- Warning signs of an approved type must be conspicuously posted outside entrance doors to rooms that contain strong magnetic fields, lasers, x-rays, high voltage devices, or other potentially hazardous radiation or equipment. Separate warning signs must be displayed outside rooms containing equipment, such as microwave sources, that could adversely affect pacemaker devices. Experiments using radioactive sources, and/or X-ray producing equipment must be completed under supervision of a competent person in accordance with the licensing requirements.
- Shielding, guarding, monitoring of ultraviolet radiation, X-rays and radioactivity is normally required by licensing regulations and experiments must comply with all applicable standards.
Contact the Environmental Health & Safety Office for more details concerning the university’s radiological control program.
Reminder: Acids and bases are always added to water. Slowly add chemicals carefully stirring to allow cooling.
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