Food Science - Virtual Chemistry Lab

Safety In The Laboratory

SAFETY REGULATIONS AND PREPARATION FOR LABORATORY WORK

THE LABORATORY WITH ITS EQUIPMENT, GLASSWARE AND CHEMICALS HAS THE POTENTIAL FOR ACCIDENTS. IN ORDER TO AVOID DANGEROUS ACCIDENTS OR TO MINIMIZE THEIR DAMAGE, PRECAUTIONS MUST BE TAKEN BY THE STUDENT AND THE INSTRUCTOR TO INSURE THE SAFETY OF EVERYONE IN THE LABORATORY.

Before each laboratory session, your instructor will discuss any safety hazards that might be associated with that day's experiment.

SAFETY IN THE LABORATORY

Laboratory safety begins with a safe attitude.

The safety precautions that follow are not meant to be an all-inclusive list of do's and don't's for laboratory work. Rather, they are a sample of the types of concerns or attitudes that can bring about a safe laboratory experience. They are not in any particular order of priority, however those items addressing protective eyewear, clothing, footwear, and the consumption of food or drink are often heavily emphasised in statements of general safety. Many other items pertain to specialised situations in the laboratory.

Protection in general

When selecting appropriate personal protective equipment, the nature of the hazard, the required degree of protection and the ease with which the equipment may be used should be considered. It should be properly selected for the task, readily available, clean and well maintained.

The Material Safety Data Sheet discussed later should be consulted when deciding on which personal protective equipment is required for work with particular chemicals.

Persons in the laboratory should be aware of the use of personal protective equipment, including its limitations and efficiency, appropriate selection and fitting, and storage and maintenance. Report all injuries.

Protective eyewear

Wear eye protection at all times when in an area where chemicals are stored or used. This includes times when personal work may have ceased but that of colleagues is still proceeding or where cleaning after an experiment is being undertaken.

The exact rules for eye protection will vary from one laboratory to another and from one situation to another as it is difficult in a laboratory situation to eliminate or totally control eye hazards. Damage to eyes can result from flying particles, dusts, gases, aerosols, splashing of chemicals or molten metals, or radiation generated from ultraviolet lights and lasers. Some laboratories consider prescription glasses adequate protection whereas others do not and demand side protection. In general, contact lenses are not considered safe in the laboratory even if covered by glasses or goggles as the vapours from various chemicals can cause eye irritation.

The risks associated with a particular task should be evaluated and appropriate eye protection such as safety spectacles, goggles or face shields selected.

Approved eye protection should comply and be used in accordance with Australian Standards.

Protective clothing

Wear a protective coat when working in a laboratory. The coat, which should be closed down the front, offers protection against splashes, contamination and dirt. Laboratory coats are available in different styles, including front buttoning, wrap around and back fastening. In some instances, overalls are used.
Tie back long hair or contain in a net.
If appropriate, wear protective gloves. The use of protective gloves minimises the hazards when working with chemicals, radioisotopes, excessive heat or cold, biological products, and animals. When choosing gloves, the nature of the potential hazard, the complexity of manual activity, the closeness of fit and whether disposable or re useable should be considered.

Protective footwear

Wear the appropriate protective footwear (closed-in shoes) when working in the laboratory. Thongs, sandals or similar footwear are not acceptable. Closed in shoes, preferably leather, provide the best protection against injury and chemical spills and in some instances steel capped shoes may be necessary. Specialised appropriate personal protection equipment (eg gum boots) should be available and worn when required or as directed by the laboratory supervisor.

Consumption of food and drink and smoking

Do not store or consume food and drink in the laboratory and do not smoke in the laboratory.
The possible dangers from accidentally ingesting materials while eating or drinking in the laboratory are severe. Smoking in the laboratory increases the potential for fires as well as the ingestion of foreign material especially that which has been pyrolysed during passage through the tip of the cigarette. Do not drink water from laboratory taps. Frequently wash hands during work in and prior to leaving the laboratory.

Work space

Become familiar with the emergency preparedness procedures. Know the location and operation of the nearest emergency shower, eyewash station, first aid kit, and fire fighting equipment. Know the location of emergency exits.
Keep corridors and doorways clear. Exercise care when opening and closing doors and entering or leaving the laboratory.
Keep your work space orderly. Books, clothing, paper towel, dirty glassware, reagent bottles and the like can pose a potential safety hazard.
Clean up work surfaces after each project or at the end of each day.
Do not indulge in or encourage careless behaviour.
When a drawer or cupboard is not actually in use, it should closed.
Avoid working alone in the laboratory alone. Let someone know of your whereabouts.

Project Preparation

Read and understand all procedures before attempting them.
Become familiar with the physical properties and potential dangers of materials you plan to use. Consider how they may react in combination.
Consult the Material Safety Data Sheets for information. (covered in detail later)
Consider the limitations of the equipment you plan to use. Think through any potential hazards associated with your work and plan your response before commencing an experiment. If available, consult any HIRAC reports.
If in doubt, ask your supervisor for assistance.

Chemical reagent handling

Consult the Material Safety Data Sheet for each chemical involved in the project to be undertaken.

Avoid tasting and smelling chemicals.

All work involving fumes or generation of aerosols must be carried out in an appropriate fume cupboard or bio-safety cabinet. Work carried out in a laboratory may generate fumes, dusts, gases or aerosols. The use of fume cupboards, glove boxes, local exhaust ventilation, biosafety cabinets and other specialised equipment is aimed at containing and controlling respiratory hazards in the working environment.

Pipetting by mouth should not be performed. Use pipette fillers or similar equipment.

Store flammable liquids in an appropriate flammable liquid cabinet or storeroom.

Secure gas cylinders upright to prevent tipping or falling.

Clean up spills immediately and thoroughly. If you are not able to rectify the situation, inform your supervisor immediately.

All chemicals should be disposed of in a manner consistent with their properties and in accordance with the accepted procedure.

Read labels on reagent bottles carefully and ensure the contents are exactly what are called for in the procedure.

Inform your supervisor if you have any allergies, sensitivities or medical conditions which might be affected adversely by exposure to specific chemicals.

To avoid contamination of initial reagents, do not insert droppers, pipettes or spatulas into reagent bottles. Dispense some reagent into a clean receptacle and dispense from there. Do not return unused chemicals to the reagent bottle. After using a reagent bottle, replace the lid.

Keep the balance and the area around it clean. Do not place chemicals directly on the balance pan or dispense them into a container on the pan. Do not weigh an object while it is hot.

Never add water to any concentrated acid, especially sulphuric acid. The acid must be slowly added to the water with stirring to allow the dissipation of heat involved in the dilution.

Glassware handling and storage

Due to its fragility and potential for serious injuries, all glassware should be handled carefully and some commonsense rules applied its storage as well as handling.

Store glassware in an easily accessible well-lit area so that it may be removed without risk of breakage. It should not be necessary to stand on anything to reach items.

Store heavy pieces low down on shelves with lighter pieces higher. Tall pieces should be at the back of shelves with smaller ones to the front.

Store delicate pieces in their original, identified cartons with moulded packaging, cotton wool, or some other support. Use cotton wool for other easily rolled items such as round bottom flasks.

When working at the laboratory bench, place tall items of glassware at the back.

Never use broken, chipped, cracked or badly scratched glassware.

Do not pick up large or small pieces of broken glass with bare hands, always use a brush and pan or suitable gloves.

Know the location of the sharps bin. (a specific container for waste or broken glassware, which should not be deposited into the normal garbage).

Place round glassware in a position where it will not roll off the bench-top. Use a beaker or cork ring to hold such pieces of apparatus.

Do not try to catch falling glassware.

Any glass apparatus that is going to be heated or cooled must be made of borosilicate ("Pyrex") glass. "Soda" glass is normally only used for storage or volumetric glassware. For applications involving heating above 250oC, silica glassware should be used.

Select clean, dry glassware and inspect each piece for faults such as cracks, chips, scratches or other internal or surface flaws.

All glass apparatus used for general laboratory operation should be constructed from round glass jointed or "Quickfit" units, set up on fixed laboratory "scaffolding" and secured to this framework by using boss heads and cork or high temperature fibre lined clamps.

For bench top experiments, apparatus should not be set up at a height that requires the operator to either stand on a platform , or to reach above his or her head.

When heating glassware, other than small test tubes, never use a naked flame directly on the glass. Use one of : a hot water or a steam bath, an infra red lamp, a steam jacket or heating tape, a heating mantle, oil or sand bath or heating block or wire gauze.

When lifting or moving hot glass beakers or flasks, always use the appropriate type and size of tongs.

Chromic acid cleaning mixtures to clean glassware should be avoided. Use surface active general purpose cleaners such as "Decon 90" . Small items may be more effectively cleaned by combining a cleaning agent with an ultrasonic bath.

Glassware should be thoroughly rinsed or decontaminated as soon as possible after use.

NEVER pipette any solution by mouth in the laboratory. Use a rubber bulb pipette filler with the pipette, or use a safety pipette, burette, Pasteur pipette, syringe, etc.

When fitting the pipette to a pipette filler, hold the pipette as close as possible to the point of entry of the filler to avoid the risk of breaking the pipette and consequent injury.

Carefully watch the pipette tip while the filler is sucking up the solution so as to avoid any sudden inflow of air.

MATERIAL SAFETY DATA SHEETS (MSDS)

Material Safety Data Sheets (MSDS) aim at providing the information required to safely store, use and dispose of substances that are handled at the workplace. In the laboratory, MSDS should be requested from the supplier whenever an initial order is placed for a particular laboratory reagent. If practical, the MSDS could be obtained in advance of the first supply of the substance, in order to assess its use and allow for any necessary modifications or controls to be implemented.

All persons required to handle or supervise the handling of chemical substances must have easy access to the MSDS for those particular reagents. MSDS may be provided in a number of forms, including paper copy, microfiche or as part of a computerised (CD ROM or on line) database. The available MSDS should be the most recent copy and all persons should be trained in how to access the information, especially if it is part of an electronic data base.

If the employer wishes to add extra information to the MSDS, this should be appended to the original document. The amendment should be clearly marked as such and should not be confused with the original information supplied.

The following information should be available from the MSDS:

the number of pages - How many pages are contained in the MSDS and which page is being referred to;
the date of issue of the MSDS;
the name of the manufacturer or supplier with the Australian address or contact;
the telephone number of the manufacturer or supplier;
an Australian telephone number to contact should an emergency occur. If there is no emergency number, the MSDS should state that no such contact is available;
relevant fax or telex numbers (optional);
the product name this should be the same name as detailed on the product label;
any other names by which the product is commonly known and its correct shipping name;
the manufacturer's product code or internal identification code;
the UN Number and Dangerous Goods Class and any subsidiary risk. This information identifies the hazard and provides information regarding emergency response;
the Poisons Schedule number or, if the substance has not been scheduled, a statement to this effect;
the major recommended uses of the product;
the physical description and properties of the substance the information in this section should include:
appearance, boiling and/or melting points; vapour pressure; specific gravity; flashpoint; flammability limits; solubility in water; any other relevant physical properties including shock sensitivity, corrosiveness, oxidising properties, reactivity with common substances, auto-ignition temperature, evaporation rate, vapour density, odour threshold, pH, solubility in organic solvents, amount of volatiles included and bulk density.
Information regarding the physical description and properties of the substance can be used in estimating potential exposure, spill response, design of engineering controls and development of safety procedures.
the chemical composition of the substance, listing each ingredient and its proportion of the product if it is a mixture. This information should also include any impurities that may be present. Each ingredient should also be listed with its CAS Number. Any solvents, including water, that are used should also be included;
the health effects of the product, including short term or acute effects and the effects of long term or chronic exposure. Information should include: health effects relating to human exposure if this data is available; relevant animal exposure data; the effects and range of symptoms of possible types of exposure, such as swallowing, inhaling, in the eye or through the skin; the dose, concentration or conditions of exposure that may commonly cause health effects; additional information including synergistic effects of smoking or alcohol intake, effects on pre existing medical conditions or possibility of allergic reactions; carcinogenicity data, including evidence from animal and possible human exposure;
first aid information, including requirements for specific facilities such as eye washes, emergency showers, the need for medical attention, treatments or antidotes for exposure, whether or not to induce vomiting;
information to be used by medical practitioners, including specific treatments and contra indicated treatments;
precautions for use of the substance, including details for developing safe work practices. This information should include: details of Australian occupational exposure standards and reference to approved Codes of Practice. Overseas exposure standards may be listed if an Australian standard does not exist. If no exposure standard has been allocated for the substance, this should be indicated in the MSDS; engineering controls, especially ventilation requirements; personal protection measures, including protection for the skin, eyes and respiratory system; flammability data, including ventilation required to prevent vapour build up, the need to avoid ignition sources and any special requirements such as flameproof fittings, earthing of containers or isolation of the substance;
safe handling information, including safe storage and transport of the substance and methods used to deal with a spill or leak. The recommendations for response to small and large spills should be differentiated;
recommendations for the safe and environmentally responsible methods of disposal of the substance, including special precautions for incineration or landfill;
information for fire fighting and emergency services, including toxic or dangerous decomposition or combustion products, types of fire extinguishers/agents, personal protective
equipment to be used and any potentially hazardous interactions with other products;
any other information that is relevant to the safe storage, use, transport or disposal of the substance, such as biodegradability, persistence in soil or water or additional animal toxicity data;
a contact point for clarification of information, including the title of the position and the telephone number.

The easiest way to access a MSDS is by using CHEMWATCH, which is available to Science & Engineering students via the UB network!!