working with “sonicator”

Sonicators are high-frequency sound generators used to disrupt cells or shear nucleic acids. Laboratory personnel must be concerned about two of the major hazards associated with sonicators. The first hazard is hearing damage caused by high frequency sound. The second hazard is the generation of aerosols from the sonication process.

Sonicators generate sound waves in the 20,000 Hz range. These sonicator-generated sound waves are outside the normal range of hearing. Often the sound heard while using a sonicator is produced by cavitations of the liquid in the sample container or vibrations from loose equipment. Actions you can take to reduce the hazards include:

• Wear earphone-type sound mufflers to protect your hearing while sonicating
   
• If possible, have the sonicator located in a “sound-proof” cabinet while sonicating
   
• Do not sonicate in a room containing people not wearing ear protection
   
• Shut doors of the room where sonication is taking place

Blending, Grinding, Sonicating, Lyophilizing

The greatest hazard when using sonicating and other equipment to disrupt cells or shear nucleic acids is the creation of aerosols. These aerosols are generated by cavitations of the sonicator horn in the sample media and mechanical mixing.  The following guidelines should be followed.

• Blenders, grinders, sonicators, lyophilizers, etc. should be operated in a biosafety cabinet whenever possible.
   
• Safety blenders should be used. Safety blenders are designed to prevent leakage from the bottom of the blender jar and to withstand sterilization by autoclaving. They also provide a cooling jacket to avoid biological inactivation.
   
• Avoiding using a glass blender jar. If a glass jar must be used, it must be covered with a polypropylene jar to contain the glass in case of breakage.
   
• A towel moistened with disinfectant should be placed over the top of the blender while operating. This practice can be adapted to grinders and sonicators as well.
   
• Aerosols must be allowed to settle for five minutes before opening the blender jar (or grinder or sonicator container).
   
• Lyophilizer vacuum pump exhaust should be filtered through HEPA filters or vented into a biosafety cabinet.
   
• Polypropylene tubes should be used in place of glass ampoules for storing biohazardous material in liquid nitrogen. Glass ampoules can explode, causing eye injuries and exposure to the biohazardous material.

Source: University of Rochester

safety rules in dealing

with perchloric acid?

FACT SHEET

Perchloric Acid Use

Some words of caution are in order. No matter how complete your list seems or how complex the compatibility matrix appears, there is always the exception chemical, the one that falls into two (or more) groups. Beware of this and seek expert advice when you are unsure about safe storage. In closing, here are a few more guidelines for safe chemical segregation:

- Do not store chemicals alphabetically as a general group. Separate into compatible groups first.
- Do not store chemicals on high shelves or in high cabinets. A good rule is to store them at eye level or below.
- Do not store chemicals on bench tops or in hoods, except for those being used currently.
- Do not store incompatible materials one above the other on shelving in the lab. Prevent any chance of accidental mixing.
- Do separate chemicals into their organic and inorganic families and then compatible groups.
- Do provide a definite storage place for each chemical and return the chemical to that location after each use.
- Do store volatile toxics and odiferous chemicals in a ventilated cabinet.
- Do store flammable liquids in approved flammable storage cabinets or safety cans.
- Do ensure that shelving materials are appropriate and compatible with the chemicals stored on them (e.g., do not store oxidizers on wooden shelves).

Finally, for those of us in seismically active regions, there are additional precautions (and probably regulations) to address. In these areas we should have lipped shelving and secured storage units, at a minimum. Check with your local authorities for additional guidance. As always, safety first.

Comments or questions are always welcome. Contact thesafetyguys@labx.com.

Vince McLeod is an American Board of Industrial Hygiene–certified industrial hygienist and the senior industrial hygienist with the University of Florida’s Environmental Health and Safety division. He has 22 years of occupational health and safety experience at the University of Florida, and he specializes in conducting exposure assessments and health hazard evaluations for the university’s 2,200-plus research laboratories.

References

1. Hazard Investigation: Improving Reactive Hazard Management. U.S. Chemical Safety and Hazard Investigation Board. Report No. 2001-01-H, NTIS No. PB2002- 108795. 2002.
2. Laboratory Safety Incidents. Laboratory Health and Safety Committee, American Industrial Hygiene Association. March 2009.
3. NFPA 55 Compressed Gases and Cryogenic Fluids Code, 2010 edition. National Fire Protection Association, Quincy, MA. 2004.

www.nfpa.org/AboutTheCodes/AboutTheCodes.asp?DocNum=55.

Some words of caution are in order. No matter how complete your list seems or how complex the compatibility matrix appears, there is always the exception chemical, the one that falls into two (or more) groups. Beware of this and seek expert advice when you are unsure about safe storage. In closing, here are a few more guidelines for safe chemical segregation:

- Do not store chemicals alphabetically as a general group. Separate into compatible groups first.
- Do not store chemicals on high shelves or in high cabinets. A good rule is to store them at eye level or below.
- Do not store chemicals on bench tops or in hoods, except for those being used currently.
- Do not store incompatible materials one above the other on shelving in the lab. Prevent any chance of accidental mixing.
- Do separate chemicals into their organic and inorganic families and then compatible groups.
- Do provide a definite storage place for each chemical and return the chemical to that location after each use.
- Do store volatile toxics and odiferous chemicals in a ventilated cabinet.
- Do store flammable liquids in approved flammable storage cabinets or safety cans.
- Do ensure that shelving materials are appropriate and compatible with the chemicals stored on them (e.g., do not store oxidizers on wooden shelves).

Finally, for those of us in seismically active regions, there are additional precautions (and probably regulations) to address. In these areas we should have lipped shelving and secured storage units, at a minimum. Check with your local authorities for additional guidance. As always, safety first.

References

1. Hazard Investigation: Improving Reactive Hazard Management. U.S. Chemical Safety and Hazard Investigation Board. Report No. 2001-01-H, NTIS No. PB2002- 108795. 2002.
2. Laboratory Safety Incidents. Laboratory Health and Safety Committee, American Industrial Hygiene Association. March 2009.
3. NFPA 55 Compressed Gases and Cryogenic Fluids Code, 2010 edition. National Fire Protection Association, Quincy, MA. 2004. www.nfpa.org/AboutTheCodes/AboutTheCodes.asp?DocNum=55.

Additional Resources

Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. National Research Council. National Academy Press. Washington, D.C. Latest edition.
NIOSH Pocket Guide to Chemical Hazards. National Institute of Occupational Safety and Health. Publication 2005-149. www.cdc.gov/niosh/npg/.
CRC Handbook of Laboratory Safety, 5th edition. CRC Press, LLC, Boca Raton, FL. 2000. Compatibility chart online here: rehs.rutgers.edu/pdf_files/ Chemical_Comp_Chart.pdf.
A Method for Determining the Compatibility of Chemical Mixtures. U.S. Environmental Protection Agency, Cincinnati, OH. EPA-600/2-80-076. 1980. Compatibility chart online here: rehs.rutgers.edu/pdf_files/ Chemical_compatibility.html.

Three simple words: “Plan → Do → Control”.

Cryogenic materials are extremely cold and call for special handling, tools and personal protection. Liquified gases will freeze skin on contact, so you should wear nonporous gloves intended for cryogenic work. Boots and long clothing will prevent accidental contact from spills. Since cryogenic temperatures can also damage many materials, use only containers and equipment designed to handle these conditions. Many people work with cryogenics every day, so using the right equipment and following simple procedures will keep them safe.

Primary Hazards

Cryogenic materials have temperatures roughly lower than -150°C. This will instantly cause frostbite or burn any exposed skin. Prolonged contact will cause serious, possibly life-threatening injury. Because of this hazard, avoid any direct contact with cryogenic solids or liquids to your skin or eyes.

Very low temperatures cause normally soft, flexible objects such as hoses, gaskets and seals to become brittle and crack. Cracked parts may have sharp edges, posing a laceration hazard. Store cryogenic materials only in containers specifically designed for the purpose. Certain closed-cell plastic foams, such as styrofoam, can contain liquid nitrogen for short periods of time. Metals will undergo thermal contraction and possibly crack. They will also become extremely cold to the touch.

Secondary Hazards 

Cryogenic liquids boil at room temperature, giving off gases. These gases will be extremely cold. While the cooling power of a gas is less than a liquid’s, you should still keep it at a safe distance. For hydrogen and liquefied natural gas (LNG), flammability is a concern. Nitrogen, argon and helium, on the other hand, are chemically inert and won’t burn, but they displace air, creating a risk of asphyxiation. Liquids boiling into gases expand volume by thousands of times, so use them only with adequate ventilation. Never store cryogenic liquids in a sealed container without pressure relief. As the liquids turn to gas, pressure will build past the container’s bursting point, possibly resulting in an explosion.

Tanks 

Cryogenic liquids are delivered and stored in special steel tanks, called dewars. Essentially, they’re giant Thermos® bottles designed to insulate the cold liquids from normal temperatures. They also have a relief-valve system that vents the gases that boil off, regardless of how well-insulated the dewar is. The tanks should be kept in a limited-access room, preferably locked. Keep the tank chained to a nearby wall to prevent tipping. 

Personal Protective Equipment

If you’re handling cryogenic materials, you need a pair of special gloves made for the purpose. They’re thick, made of rubber and cloth, and cover the skin up to the elbows. The rubber prevents any cold liquids from seeping in. In addition, closed-toe shoes or boots and long pants are essential to prevent skin contact in case of spills. A full-face shield and rubber apron will afford extra protection, especially if you expect splattering. 

Use 

For general use, dispense cryogenic liquids from a large supply, such as the tank mentioned above, into small, portable dewars. After filling but before use, keep the small dewar in a safe, stable place. Handle supercooled objects with gloves or tongs. To freeze biological specimens, use only containers meant for the purpose.

Source: eHow.com

Cryogenic materials are extremely cold and call for special handling, tools and personal protection. Liquified gases will freeze skin on contact, so you should wear nonporous gloves intended for cryogenic work. Boots and long clothing will prevent accidental contact from spills. Since cryogenic temperatures can also damage many materials, use only containers and equipment designed to handle these conditions. Many people work with cryogenics every day, so using the right equipment and following simple procedures will keep them safe.

Primary Hazards

Cryogenic materials have temperatures roughly lower than -150°C. This will instantly cause frostbite or burn any exposed skin. Prolonged contact will cause serious, possibly life-threatening injury. Because of this hazard, avoid any direct contact with cryogenic solids or liquids to your skin or eyes.      

Very low temperatures cause normally soft, flexible objects such as hoses, gaskets and seals to become brittle and crack. Cracked parts may have sharp edges, posing a laceration hazard. Store cryogenic materials only in containers specifically designed for the purpose. Certain closed-cell plastic foams, such as styrofoam, can contain liquid nitrogen for short periods of time. Metals will undergo thermal contraction and possibly crack. They will also become extremely cold to the touch.

Secondary Hazards

Cryogenic liquids boil at room temperature, giving off gases. These gases will be extremely cold. While the cooling power of a gas is less than a liquid’s, you should still keep it at a safe distance. For hydrogen and liquefied natural gas (LNG), flammability is a concern. Nitrogen, argon and helium, on the other hand, are chemically inert and won’t burn, but they displace air, creating a risk of asphyxiation. Liquids boiling into gases expand volume by thousands of times, so use them only with adequate ventilation. Never store cryogenic liquids in a sealed container without pressure relief. As the liquids turn to gas, pressure will build past the container’s bursting point, possibly resulting in an explosion.

Tanks

Cryogenic liquids are delivered and stored in special steel tanks, called dewars. Essentially, they’re giant Thermos® bottles designed to insulate the cold liquids from normal temperatures. They also have a relief-valve system that vents the gases that boil off, regardless of how well-insulated the dewar is. The tanks should be kept in a limited-access room, preferably locked. Keep the tank chained to a nearby wall to prevent tipping.

Personal Protective Equipment 

If you’re handling cryogenic materials, you need a pair of special gloves made for the purpose. They’re thick, made of rubber and cloth, and cover the skin up to the elbows. The rubber prevents any cold liquids from seeping in. In addition, closed-toe shoes or boots and long pants are essential to prevent skin contact in case of spills. A full-face shield and rubber apron will afford extra protection, especially if you expect splattering.

Use

For general use, dispense cryogenic liquids from a large supply, such as the tank mentioned above, into small, portable dewars. After filling but before use, keep the small dewar in a safe, stable place. Handle supercooled objects with gloves or tongs. To freeze biological specimens, use only containers meant for the purpose.

Source: eHow.com

The purpose of a correct implication of SOPs are:

- Understand the mandates for clearly delineated processes set forth by the Food and Drug Administration (FDA), International Conference on Harmonization (ICH), Occupational Safety and Health Administration (OSHA), the International Organization for Standardization (ISO), and other governing bodies

- Have increased understanding of the role of written procedures in maintaining effective and compliant business activities

- Understand the importance of document integrity and established controls

- Understand how to prevent overlaps, contradictions, and disconnects in documents

- Have increased confidence in planning and writing various process documents

- Understand how English tenses work and how they serve to make process documents clear and logical

- Understand how to write in the third person, use the imperative voice, and pare the passive

- Be able to control the language so that every word counts and messages are clear to readers

- Know the answers to your questions about language anomalies

- Understand the industry standards for procedure writing, including typical components of documents, and using document templates

- Know how to review and revise documents

- Understand the full life cycle of SOPs and other documents

- Understand how training is integral to document approval

- Know how to build a non-binding style guide to support the writing process.