Lab Safety First

Health & Safety

- You should think of “safety” while doing any practical work to avoid harming yourself or others.

- Safety is considered everyone responsibility.

COSHH Control of Substances Hazardous to Health - Are group of “regulations” including specific legal requirements for risk assessment when using hazardous chemical or biological agents. - These regulations can be applied through ‘approved’ codes of practice for the control of hazardous substances, carcinogens and biological agents, including pathogenic microbes.

Hazard & Risk Hazard: the ability of a substance or biological agent to cause Harm.

Risk: the pRobability of a substance or biological agent to cause harm in a specific situation.

How to differentiate between Hazard and Risk: One of the Hazards associated with water is drowning. However, the Risk of drowning in a few drops of water is minimal !!

Warning Signs Radiation hazard

Toxic

Laser Hazard

Flammable- oxidizing

US protectors Emergency eye wash

Explosive

Low temperature

Exposure Routes to Harmful substances

1- Skin Absorption Some materials are capable of penetrating intact, healthy skin as phenol

3- Ingestion Accidental on contaminated food, drink

2- Inhalation Of gases, vapours, aerosols, fumes

4- Injection

Biological Hazard - The most obvious risks when handling microbial cultures are those due to ingestion or entry via a cut in the skin.

- All cuts should be covered with a plaster or disposable plastic gloves.

- A less obvious source of hazard is the formation of aerosols of liquid droplets from microbial suspensions, with the risk of inhalation, or surface contamination of other objects.

Classification of microbes on the basis of hazard, UK Advisory Committee on Dangerous Pathogens (ACDP) Hazard group

Comments

1

Unlikely to cause human disease.

2

May cause disease - Possible hazard to laboratory workers / minimal hazard to community.

3

May cause sever disease - May be a serious hazard to laboratory workers / may spread to community.

4

Causes sever disease - Is a serious hazard to laboratory workers / high risk to community.

Laminar flow cabinet - Prevent airborne contamination e.g. when preparing media or sub-culturing microbes or tissue cultures. - Sterile air is produced by passage through a high efficiency particulate air (HEPA) filter, which is then directed towards the working area, either horizontal towards the operator or downwards. - No protection to the worker from contamination and so, must not be used with pathogenic microbes.

Bio-safety Labs 4 bio-safety levels (BSLs) according to different laboratory techniques, safety equipment, and design, depending on the types of agents being studied: BSL-1 labs: used to study agents not known to consistently cause disease in healthy adults. - Basic safety procedures - no special equipment or design features. BSL-2 labs: used to study moderate-risk agents that pose a danger if accidentally inhaled, swallowed or exposed to the skin. - Safety measures: gloves - eyewear - hand washing sinks - waste decontamination facilities. BSL-3 labs: used to study agents that can be transmitted through the air and cause potentially lethal infection. - Safety measures: Gas-tight enclosure - specialized ventilation system - clothing decontamination - sealed windows. BSL-4 labs: used to study agents that pose a high risk of life-threatening disease for which no vaccine or therapy is available. - Safety measures: wearing full-body, air-supplied suits - shower when exiting the facility - occupy safe, isolated zone within the building.

Substance

Hazard

SDS ‘sodium dodecyl -Irritant sulphate’ -Toxic NaOH ‘sodium hydroxide’

Safety Wear gloves

- sever irritant - highly corrosive

Wear gloves

Isopropanol

- irritant/corrosive - highly flammable - potential carcinogen

Wear gloves No naked flames

Phenol

- highly toxic - skin burns - potential carcinogen

Wear gloves Use in fume hood

Chloroform

- volatile and toxic - irritant/corrosive -potential carcinogen

Wear gloves Use in fume hood

Ethidium bromide and COSHH - Ethidium bromide (EtBr) is widely used for detection and quantification of DNA/RNA, but is an extremely hazardous material. - The ready prepared ethidium bromide solutions decrease the risk associated with handling the solid when preparing the stock solutions. Risks associated with ethidium bromide: R 22 Harmful if swallowed R 23 Very Toxic by inhalation R 68 Possible risks of irreversible mutagenesis effect: intercalating agent and frame-shift mutagen. *R: indication of risk associated. - Inexpensive, but the hidden costs of disposal are very high. charcoal filters, operator time to filter the waste running buffer, and bagging of solid waste for incineration.

Disposal of ethidium bromide: - Aqueous solutions of ethidium bromide (>1.0µ g/ml) may be disposed of in one of two ways: 1- Adsorbed onto an ‘ion exchange column’ specifically for this purpose, These columns will adsorb at least 300mg of ethidium bromide; the waste liquid may then be discarded to drain. Then, the columns should be double-bagged in plastic bags and disposed of as for solid waste. 2- Adsorbed onto activated charcoal at a rate of 100mg charcoal to 50mg ethidium bromide. The mixture should be left overnight before filtering off the solid, which should then be double-bagged in plastic bags, then disposed of as for solid waste. And the waste liquid can be discarded to drain. Solid ethidium bromide waste (e.g. gels, contaminated paper towels, etc) should be placed into a suitable, leak-tight container and then into a yellow bag and treated as clinical waste for incineration.

SYBR Safe Green - An alternative of the ‘ethidium bromide’. - No acute oral toxicity and greatly reduced genotoxicity. - Non hazardous waste. - No special handling, storage or disposal. -Can be excised from gels under non-UV light, which reduces UV-induced cross-linking of the DNA you want to further manipulate.

But more expensive!!

References: Books: - Reviewed in Practical skills in biology, 2003