BABCOCK UNIVERSITY DEPT OF MEDICAL LABORATORY SCIENCE LECTURE

BABCOCK UNIVERSITY DEPT OF MEDICAL LABORATORY SCIENCE LECTURE TOPIC: LABORATORY SAFETY CODE: MLSC 202 1

• Objectives • At the end of the lecture, the students ahould be able to: • 1. Define laboratory safety. • 2. List 5 laboratory hazards. • 3. Name 6 universal safety precautions in the laboratory 2

• SAFETY IN THE LABORATORY -AN OVERVIEW The practice of medical laboratory science is associated with hazards and accidents: Biorisks The laboratory worker is very much at risk of acquiring transmissible diseases through contact with patients or handling of clinical specimens. He/she also faces other hazards when carrying out his/her duty. 3

• And accidents do occur even in the best of laboratories. • But a poorly designed and overcrowded laboratory increases the risk of hazards and accidents. • Bad laboratory practices are the major causes of laboratory accidents. • It is important that all accidents be promptly reported to the safety officer or to the officer incharge of the laboratory. 4

HAZARDS IN THE LABORATORY Hazards and accidents in the laboratory may be discussed under the following topics: 1. Infection 2. Burns 3. Cuts and pricks 4. Toxic chemicals 5

Infection The commonest causes of infection are: a. Inhalation of pathogens in air-borne droplets (aerosols) which are released during breakage or spilling of infectious fluids, centrifuging, dispensing or pipetting of infectious materials; and snap-opening and closing of specimen containers. b. Ingestion of pathogens from contaminated food or fingers. 6

c. Ingestion of pathogens by mouth-pipetting d. Pathogens finding their way into the body through needle pricks and cuts etc. 2. Burns sustained in the laboratory may be caused by: a. Inflammable substances catching fire. 7

b. Fires from bunsen burner, spirit lamps or from faulty or overloaded electric circuit. c. Swallowing of corrosive substances during pipetting or spilling such substances on the skin. 3. Cuts and pricks may result from: a. Edges of broken glasswares 8

4. a. Edge of a knife b. Accidental pricking with needle c. Walking on glass chippings Hazards of toxic chemicals Hazards due to toxic chemicals result from: 9

a. Inhalation of fumes of toxic chemicals b. Swallowing or ingesting toxic chemicals during mouth pipetting a. Skin contact with toxic chemicals. 10

5. Electric shocks usually due to ignorance or carelessness can be caused by a. Faulty electrical circuits b. Incorrect installation of equipment c. Touching exposed live wires 11

UNIVERSAL PRECAUTIONS AGAINST INFECTION 1. Wear protective clothing (laboratory coats/gowns) over normal clothing; preferably, wear closed shoes; and do not walk barefooted in the laboratory. 2. Handle all specimens and infected materials with care 3. Avoid eating, drinking or chewing gum in the laboratory. 12

4. Refrain from smoking in the work zone of the laboratory. 5. Refrain from applying cosmetics in the laboratory. 6. Never pipette with the mouth. Do not lick gummed labels, or put pens or pencils in the mouth, or stick them in the hair. 13

7. Wear protective gloves and plastic aprons when collecting blood sample for hepatitis, AIDS or viral haemorrhagic fever investigations. 8. It is not advisable to recap used needles. Instead, "Sharpsafe" containers should be made available for the immediate disposal of used needles. The containers are finally incinerated 14

. 9. Wear gloves when handling specimens or culture containing highly infectious pathogens. 10. Keep finger nails short. 11. Disinfect all infected or contaminated materials before disposal. 12. Place a jar of disinfectant on each bench. 15

• PREVENTION OF OTHER LABORATORY HAZARDS: The prevention of common hazards and accidents is very well documented in many laboratory manuals. • It is very necessary that all members of the laboratory staff are conversant with the nature of these hazards and their prevention. 16

. The very common accidents even in the smallest laboratories are mainly due to the following: - Dangerous Chemicals - Fire - Careless use of laboratory equipment and reagents. 17

Dangerous Chemicals - These dangerous chemicals include the highly flammable ones like ether or alcohols, highly corrosive ones like phenol 'or sulphuric acid, toxic ones like formaldehyde solution, carcinogenic ones like benzidine or explosive ones like picric acid. - To minimise accidents caused by the chemicals, manufacturers should label dangerous chemicals with hazard symbols and supply simple instructions for use and storage. 18

• The laboratory should label clearly those reagents prepared from the dangerous chemicals. • Store rooms in which bulk stocks of chemicals are kept should be specially designed to reduce the risk of fire. • Fire extinguishers should be placed just outside the store rooms. Radioactive substances require proper supervision of their storage as provided for by the law. 19

Flammable chemicals These chemicals should be stored in fire-proof metal boxes at ground level preferably in an outside cool locked store. A bottle of ether should be opened at least 3 meters away from naked light. No smoking rule must be enforced in the laboratory at all times. 20

Corrosive substances - Corrosive chemicals such as strong acids (e. g. concentrated sulphuric or nitric acid) and caustic alkalis (e. g. sodium hydroxide, potassium hydroxide) should be stored at floor level. - Never mouth pipette a corrosive liquid; always use an automatic pipetter or dispenser. - Protect the eyes from the fumes of corrosive substances. 21

- When mixing, always add acid slowly to water, but never the reverse. - In case of any spillage, wear protective footwear when cleaning up the area. - Wash acid and alkali burns under a free stream of running cold water. 22

Toxic and irritating chemicals: - Toxic chemicals are equally irritating and can cause death or serious ill-health if swallowed, inhaled or allowed to come in contact with the skin. - Wear protective gloves when handling a toxic substance. - Always wash hands immediately after using a toxic or harmful chemical. - Chemicals such as formaldehyde or ammonia with 23

irritating or harmful vapour should be used in a fume cupboard or safety cabinet - Always use an automatic pipetter or dispenser to measure a toxic chemical. Carcinogenic chemicals These chemicals are capable of causing cancer when inhaled, ingested or in contact with the skin. The carcinogenic substance should be stored in a closed container. 24

- Wear protective gloves and a face mask when handling a carcinogen. - Wash everything used in handling the carcinogen thoroughly in cold water. Explosive chemicals - An explosive chemical can explode as a result of heat, flame or friction. - Chemicals such as picric acid should be stored under water. 25

Fire can break out in any laboratory if proper safety precautions are not observed. Fire can be caused by: - Ordinary combustibles such as paper, wood etc. - Flammable liquids such as ether, alcohols etc. - Gases such as methane. 26

- Metals such as magnesium potassium etc. - Faulty electric circuits or appliances Precautionary measures against fire 1. The laboratory staff should undergo fire drills from time to time. 2. Flammable liquids should be kept away from naked flame. 27

- Fire extinguishers should always be free and in good working condition. - In case of a major fire outbreak, safety/fire officer of the department, should take charge of fighting the fire. Equipment or instrument-related accidents - These accidents occur as a result of incorrect positioning, installation and wrong use of equipment or instrument. 28

Poor maintenance and irregular servicing of equipment also lead to accidents. • DISOPOSAL OF LABORATORY WASTE. • Disposal of laboratory waste is part and parcel of laboratory sefety. • Lots of waste are generated in the diagnostic laboratory on daily basis. They are also sources of infection and hazards. 29

The laboratory waste may classified into: - Ø Ø Ø Solid e. g. Used culture plate Liquid e. g. Urine sample Sharps e. g. Used needle Non sharps e. g. Syringe Radioactive All wastes except sharps must first be decontaminated before final disposal. The use of double autoclavable bags are recommended. The bags should be half full, 30

• tied loosely and autoclaved. The non reusable wastes are then sent to be incinerated or buried. • The reusable ones are then washed, dried and sterilised for reuse. • Sharps are placed in special puncture proof boxes. When three quarter full, they are sent to the incinerator or land fill for burial. • NOTE: SAFETY IN THE LABORATORY IS EVERYBODY’S BUSINESS. 31