Chemical Use and Hazard Management Continued

Session 6Session 6

Laboratory Safety TrainingLaboratory Safety Training

2

Compressed Gases

Average cylinder weighs 140 lbs and Average cylinder weighs 140 lbs and has 3000 psi of pressure.has 3000 psi of pressure.

Dot code stamp on neck and last test Dot code stamp on neck and last test date, steel every 10 years.date, steel every 10 years.

Spot checks of cylinders reveal 10% Spot checks of cylinders reveal 10% were significantly beyond the test date.were significantly beyond the test date.

Call the distributor whenever you find Call the distributor whenever you find them and have them supply new ones.them and have them supply new ones.

3

Compressed Gases Cont.

Types of gas in each cylinder must be Types of gas in each cylinder must be properly labeled, color codes are properly labeled, color codes are unreliable do not use them! unreliable do not use them!

Store similar types together, separate Store similar types together, separate flammable from oxidizers by at least 25 flammable from oxidizers by at least 25 ft or a fire wall at least 5ft high with a ft or a fire wall at least 5ft high with a 30 minute rating. 30 minute rating.

4

Compressed Gases Cont.

Empties should be separate from full cylinders Empties should be separate from full cylinders and the area should be labeled.and the area should be labeled.

Cylinders should never be stored or used in Cylinders should never be stored or used in any way that:any way that: blocks a means of egress blocks a means of egress inhibits flow to a fume hood inhibits flow to a fume hood where they could be struck by moving equipmentwhere they could be struck by moving equipment

5

Compressed Gases Cont.

Always store cylinders in an upright Always store cylinders in an upright position.position.

Cylinders should be transported by using a Cylinders should be transported by using a hand truck where it is strapped in wellhand truck where it is strapped in well

Never move by rolling them!!Never move by rolling them!!

Caps must be in place when movingCaps must be in place when moving

6

Compressed Gases Cont.

Cylinders must always be secure in the Cylinders must always be secure in the lab with an adjustable chain or strap with lab with an adjustable chain or strap with no slack, free standing units work well no slack, free standing units work well where there is no surface to secure to.where there is no surface to secure to.

Use valves appropriate to the gas, Never Use valves appropriate to the gas, Never lubricate valves. Never use homemade lubricate valves. Never use homemade adaptors or modify valves unless you adaptors or modify valves unless you have the manufacturers approval.have the manufacturers approval.

Never used compressed gas to blow dust Never used compressed gas to blow dust or dirt.or dirt.

7

Compressed Gases Cont.

Understand a sudden release of Understand a sudden release of compressed gas can cause an compressed gas can cause an unsecured gas hose to whip unsecured gas hose to whip dangerously causing static charges that dangerously causing static charges that could ignite a flammable gas.could ignite a flammable gas.

Always turn the gas off first before Always turn the gas off first before extinguishing a flame.extinguishing a flame.

Never bleed cylinders empty.Never bleed cylinders empty.

8

Compressed Gases Cont.

Do not put oil or grease on the high-Do not put oil or grease on the high-pressure side of an oxidizing gas (Opressure side of an oxidizing gas (O22, , Cl ) or an explosion could occur.Cl ) or an explosion could occur.

Always use the correct type of tubing Always use the correct type of tubing for the gas and ensure it is sound, e.g. for the gas and ensure it is sound, e.g. do not use copper with acetylene, do not use copper with acetylene, explosive acetylides could form. Flash explosive acetylides could form. Flash arrestors should also be used with arrestors should also be used with acetylene.acetylene.

9

Compressed Gases Cont.

Toxic gas should always be used in a Toxic gas should always be used in a fume hood or ventilated cabinet and fume hood or ventilated cabinet and check for leaks using soap solutions.check for leaks using soap solutions.

Safety glasses must always be worn Safety glasses must always be worn when working with compressed gases.when working with compressed gases.

If your cylinder is leaking and you can If your cylinder is leaking and you can not stop it open a window (if possible) not stop it open a window (if possible) turn off all reactions and get out.turn off all reactions and get out.

10

Cryogens

A liquefied gas is a gas that is less than A liquefied gas is a gas that is less than 73.3 C (-100 F). 73.3 C (-100 F).

Most common are Ar O, He, N, H, CHMost common are Ar O, He, N, H, CH44.. Most have a very high expansion ratio Most have a very high expansion ratio

and can cause asphyxiation if this and can cause asphyxiation if this occurs in poorly ventilated or small occurs in poorly ventilated or small rooms.rooms.

Flammability can be a problem.Flammability can be a problem.

11

Cryogens Cont.

Liquid He, and N can, under the right Liquid He, and N can, under the right conditions, condense Oxygen from the air conditions, condense Oxygen from the air causing oxygen enrichment (fire hazard).causing oxygen enrichment (fire hazard).

Burns to the skin can result from direct Burns to the skin can result from direct contact with a cryogen, un-insulated contact with a cryogen, un-insulated piping, or equipment containing a piping, or equipment containing a cryogen.cryogen.

Permanent damage can occur if liquid Permanent damage can occur if liquid cryogen gets into the eye.cryogen gets into the eye.

12

Cryogens Cont. The properties of some materials change The properties of some materials change

drastically at very cold temperatures: ductile drastically at very cold temperatures: ductile materials can become brittle, material materials can become brittle, material shrinkage can exceed anticipated values, and shrinkage can exceed anticipated values, and leaks can develop that are undetectable even leaks can develop that are undetectable even under pressure. under pressure.

Storage must be in an insulated dewar flask of Storage must be in an insulated dewar flask of glass or metal. Try to avoid exposed portions of glass or metal. Try to avoid exposed portions of glass, if so, tape to prevent injury if it explodes glass, if so, tape to prevent injury if it explodes (unless it is an oxidizer). A loose fitting lid (unless it is an oxidizer). A loose fitting lid should be on to allow for escaping gas and to should be on to allow for escaping gas and to prevent air or moisture from getting in.prevent air or moisture from getting in.

13

Cryogens Cont. When there is the possibility of contact with a When there is the possibility of contact with a

cryogen always wear full face shields aprons, cryogen always wear full face shields aprons, gloves or mitts. gloves or mitts.

Helium and hydrogen can solidify atmospheric air. Helium and hydrogen can solidify atmospheric air. If air is not excluded from systems containing If air is not excluded from systems containing these cryogens, vents or exhaust ports to the these cryogens, vents or exhaust ports to the atmosphere (relied upon for pressure relief) may atmosphere (relied upon for pressure relief) may become plugged by solidified air and lead to become plugged by solidified air and lead to system overpressure and vessel failure. Also, if air system overpressure and vessel failure. Also, if air condenses between the exterior metal surface of condenses between the exterior metal surface of the system and the insulating layer, when it warms the system and the insulating layer, when it warms and vaporizes it can rip off the insulation with and vaporizes it can rip off the insulation with explosive force.explosive force.

14

Cryogens Cont.

Liquid cryogens warmed above critical Liquid cryogens warmed above critical temperatures will generate high pressures. temperatures will generate high pressures. This can cause a confining vessel to rupture or This can cause a confining vessel to rupture or even explode. For example, small containers even explode. For example, small containers such as stoppered test tubes have over-such as stoppered test tubes have over-pressurized and produced flying fragments. pressurized and produced flying fragments. Fully containing a cryogenic fluid as a liquid at Fully containing a cryogenic fluid as a liquid at room temperature is usually not feasible-e.g., room temperature is usually not feasible-e.g., the pressure required to maintain liquid the pressure required to maintain liquid nitrogen at room temperature is 43,000 psi. nitrogen at room temperature is 43,000 psi.

15

Cryogens Cont.

Cryogens can create oxygen deficiency because Cryogens can create oxygen deficiency because they have large liquid-to-gas expansion ratios they have large liquid-to-gas expansion ratios (generally >700). A small liquid spill produces a (generally >700). A small liquid spill produces a large volume of gas that can displace the air in a large volume of gas that can displace the air in a confined space, thus creating a serious oxygen confined space, thus creating a serious oxygen deficiency that can suffocate occupants of the deficiency that can suffocate occupants of the area. area.

Some cryogens are chemically very reactive Some cryogens are chemically very reactive (e.g., O(e.g., O22); others are flammable (e.g., H); others are flammable (e.g., H22 and and

CHCH44). ).

16

Cryogens Cont.

Cryogenic fluids with a boiling point Cryogenic fluids with a boiling point below that of liquid oxygen may below that of liquid oxygen may condense oxygen from the air if condense oxygen from the air if exposed to the atmosphere. exposed to the atmosphere.

Because oxygen does not evaporate as Because oxygen does not evaporate as rapidly as liquid nitrogen, it will rapidly as liquid nitrogen, it will accumulate and may cause violent accumulate and may cause violent reactions with incompatible materials in reactions with incompatible materials in the systemthe system

17

Ionizing Radiation Three types of radiation emitted from various Three types of radiation emitted from various

isotopes isotopes Alpha charged particles containing 2 Alpha charged particles containing 2

protons, 2 neutrons. protons, 2 neutrons. Can be emitted by from certain heavy Can be emitted by from certain heavy

atoms such as uranium and thorium. Move atoms such as uranium and thorium. Move in straight lines, slowly. Can be stopped by in straight lines, slowly. Can be stopped by a piece of paper or by skin, but if inhaled or a piece of paper or by skin, but if inhaled or gets into an open wound can very damaging gets into an open wound can very damaging inside the body.inside the body.

18

Ionizing Radiation ßß - - Beta particles electrons emitted with very Beta particles electrons emitted with very

high energy from many radioisotopes. high energy from many radioisotopes. Positively charged counterparts of beta Positively charged counterparts of beta

particles are called positrons and can be particles are called positrons and can be shielded by thin metal foils or ¼ inch plastic. shielded by thin metal foils or ¼ inch plastic.

• Examples are tritium, phosphorus-32, Examples are tritium, phosphorus-32, and carbon-14. and carbon-14.

• can be stopped by the skin can be stopped by the skin • can cause serious damage to the eyes can cause serious damage to the eyes

and to the skin.and to the skin.

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Ionizing Radiation Cont. Gamma rays and x-rays , extremely energetic Gamma rays and x-rays , extremely energetic

photons, have no mass or charge. photons, have no mass or charge. Gamma rays are emitted from the nucleus during Gamma rays are emitted from the nucleus during

decay,and can be produced by particle accelerators, decay,and can be produced by particle accelerators, and nuclear reactors. X-rays are are emitted from and nuclear reactors. X-rays are are emitted from the electron shells. the electron shells.

Extremely dense materials, such as lead or depleted Extremely dense materials, such as lead or depleted uranium are needed to shield these particles. uranium are needed to shield these particles.

Neutrons – Uncharged particles, emitted from the Neutrons – Uncharged particles, emitted from the nucleus during decay. Can be shielded by water nucleus during decay. Can be shielded by water paraffin, boron, and concrete.paraffin, boron, and concrete.

20

Ionizing Radiation Cont.

The Threshold Limit Values (TLVs) published The Threshold Limit Values (TLVs) published by the ACGIH (American Conference of by the ACGIH (American Conference of Governmental Industrial Hygienists) are used Governmental Industrial Hygienists) are used in many jurisdictions occupational exposure in many jurisdictions occupational exposure limits or guidelines:limits or guidelines: 20 mSv - TLV for average annual dose for 20 mSv - TLV for average annual dose for

radiation workers, averaged over five yearsradiation workers, averaged over five years 1 mSv - Recommended annual dose limit for 1 mSv - Recommended annual dose limit for

general public (ICRP - International general public (ICRP - International Commission on Radiological Protection). Commission on Radiological Protection).

21

Ionizing Radiation Cont.

TlV’s Continued:TlV’s Continued: 1rem = 20 mSv, 1 S=100rem.1rem = 20 mSv, 1 S=100rem.

Half life , Half life , 125 125 I - 60 days, I - 60 days, 131131 I – 8 days I – 8 days activity is reduced by half.activity is reduced by half.

22

Ionizing Radiation Cont. The average lifetime risk of death from cancer The average lifetime risk of death from cancer

following an acute dose equivalent to all body following an acute dose equivalent to all body organs of 0.1 Sv (10 rem) is estimated to be organs of 0.1 Sv (10 rem) is estimated to be 0.8%0.8%

This increase in lifetime risk is about 4% of the This increase in lifetime risk is about 4% of the current baseline risk of death due to cancer in current baseline risk of death due to cancer in the United States. The current baseline risk of the United States. The current baseline risk of cancer induction in the United States is cancer induction in the United States is approximately approximately 25%.25%.  Another way of stating this  Another way of stating this risk: risk:

  A dose of A dose of 10 mrem10 mrem creates a risk of death from cancer creates a risk of death from cancer

of approximately of approximately 1 in 1,000,0001 in 1,000,000. .

23

Ionizing Radiation Cont.

Damage occurs to the body through Damage occurs to the body through interaction with a part of the cell or interaction with a part of the cell or indirectly by the formation of free indirectly by the formation of free radicals and ultimately changes within radicals and ultimately changes within the DNA of the cell. the DNA of the cell.

The amount of damage depends on The amount of damage depends on many factors including the dose rate, many factors including the dose rate, the size of the dose, the site of the size of the dose, the site of exposure.exposure.

24

Ionizing Radiation Cont.

Effects may be short or long term, acute Effects may be short or long term, acute short term effects = 100,000 mrads (100 short term effects = 100,000 mrads (100 rad) in less than 1 week will cause rad) in less than 1 week will cause nausea, diarrhea, fatigue, hair loss, nausea, diarrhea, fatigue, hair loss, sterility and easy bruising. Over 600 rads sterility and easy bruising. Over 600 rads is fatal. Long term low exposures can is fatal. Long term low exposures can lead to cancer.lead to cancer.

No completely safe limit of exposure is No completely safe limit of exposure is known which is why we try to reduce known which is why we try to reduce exposures to ALARA (as low as exposures to ALARA (as low as reasonably achievable) levels. reasonably achievable) levels.

25

Lasers

Class 1Class 1 - Not able to cause biological injury, - Not able to cause biological injury, exempt from any controls. exempt from any controls.

A Class 1 laser is considered safe based upon A Class 1 laser is considered safe based upon current medical knowledge. current medical knowledge.

This class includes all lasers or laser systems This class includes all lasers or laser systems which cannot emit levels of optical radiation above which cannot emit levels of optical radiation above the exposure limits for the eye under any the exposure limits for the eye under any exposure conditions inherent in the design of the exposure conditions inherent in the design of the laser product. laser product. There may be a more hazardous laser embedded in the There may be a more hazardous laser embedded in the

enclosure of a Class 1 product, but no harmful radiation enclosure of a Class 1 product, but no harmful radiation can escape the enclosure.can escape the enclosure.

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Lasers Cont. Class 2a & 2bClass 2a & 2b- Ocular hazard only if viewed for - Ocular hazard only if viewed for

more than the blink response (0.25 seconds). All more than the blink response (0.25 seconds). All wavelengths are of the visible (0.4-0.7wavelengths are of the visible (0.4-0.7 m) portion m) portion of the electromagnetic spectrum and less than of the electromagnetic spectrum and less than 1mW of power. A Class 2 laser or laser system must 1mW of power. A Class 2 laser or laser system must emit a visible laser beam. Because of its brightness, emit a visible laser beam. Because of its brightness, Class 2 laser light will be too dazzling to stare into Class 2 laser light will be too dazzling to stare into for extended periods. Momentary viewing is not for extended periods. Momentary viewing is not considered hazardous since the upper radiant considered hazardous since the upper radiant power limit on this type of device is less than the power limit on this type of device is less than the MPE (Maximum Permissible Exposure) for MPE (Maximum Permissible Exposure) for momentary exposure of 0.25 second or less. momentary exposure of 0.25 second or less. Intentional extended viewing, however, is Intentional extended viewing, however, is considered hazardous.considered hazardous.

27

Lasers Cont. Class 3Class 3 laser or laser system can emit any laser or laser system can emit any

wavelength, but it cannot produce a diffuse (not wavelength, but it cannot produce a diffuse (not mirror-like) reflection hazard unless focused or mirror-like) reflection hazard unless focused or viewed for extended periods at close range. viewed for extended periods at close range.

It is also not considered a fire hazard or serious It is also not considered a fire hazard or serious skin hazard. skin hazard.

Any continuous wave (CW) laser that is not Any continuous wave (CW) laser that is not Class 1 or Class 2 is a Class 3 device if its Class 1 or Class 2 is a Class 3 device if its output power is 0.5 W or less. output power is 0.5 W or less. Since the output beam of such a laser is definitely Since the output beam of such a laser is definitely

hazardous for intra-beam viewing, control measures hazardous for intra-beam viewing, control measures center on eliminating this possibility center on eliminating this possibility

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Lasers Cont. Class 3aClass 3a- Ocular and skin hazard for direct - Ocular and skin hazard for direct

exposures. Beams may include wavelengths of exposures. Beams may include wavelengths of visible, infrared or ultraviolet ranges. CW’s visible, infrared or ultraviolet ranges. CW’s maximum power between 1mW and 5mW. Pulsed maximum power between 1mW and 5mW. Pulsed radiant energy cannot exceed 0.125J with radiant energy cannot exceed 0.125J with exposure time <0.25s. exposure time <0.25s.

Class 3bClass 3b- Beams may include wavelengths of - Beams may include wavelengths of visible, infrared, or ultraviolet ranges. Emit no visible, infrared, or ultraviolet ranges. Emit no more than 5mW-500mW (or 5W) of CW power or more than 5mW-500mW (or 5W) of CW power or 10 J/cm10 J/cm22 of Pulsed power. Acute hazard to eyes of Pulsed power. Acute hazard to eyes and skin from direct beam. Diffuse reflections may and skin from direct beam. Diffuse reflections may be a hazard. be a hazard.

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Lasers Cont. Class 4Class 4 laser or laser system is any that laser or laser system is any that

exceeds the output limits (Accessible Emission exceeds the output limits (Accessible Emission Limits, AEL's) of a Class 3 device. Limits, AEL's) of a Class 3 device. As would be expected, these lasers may be either a As would be expected, these lasers may be either a

fire or skin hazard or a diffuse reflection hazard. Very fire or skin hazard or a diffuse reflection hazard. Very stringent control measures are required for a Class 4 stringent control measures are required for a Class 4 laser or laser system.laser or laser system.

Class 4- Ocular and skin hazard to the direct Class 4- Ocular and skin hazard to the direct beam and the diffuse reflections. Beams may beam and the diffuse reflections. Beams may include wavelengths of visible, ultraviolet or include wavelengths of visible, ultraviolet or infrared ranges. CW power greater than 5W, or infrared ranges. CW power greater than 5W, or pulsed radiant energy greater than 10J/cmpulsed radiant energy greater than 10J/cm22. . Possible ignition/fire hazard.Possible ignition/fire hazard.

30

Lasers Cont.

Some general safety tips/measures for Some general safety tips/measures for Class 3B and Class 4 lasers include:Class 3B and Class 4 lasers include: Provide key switch interlock systems to prevent Provide key switch interlock systems to prevent

unauthorized use. unauthorized use. Wear laser goggles that match the wavelength of Wear laser goggles that match the wavelength of

the laser system being used. the laser system being used. Prevent reflection of beams - be aware of Prevent reflection of beams - be aware of

windows, smooth surfaces and mirrors, watches, windows, smooth surfaces and mirrors, watches, etc. in your lab. etc. in your lab.

Prevent scattered light emissions with beam Prevent scattered light emissions with beam stops. stops.

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Lasers Cont. Never align the beam with unprotected eyes. Never align the beam with unprotected eyes.

Never intentionally stare into any laser beam. Never intentionally stare into any laser beam.

The most important safety measure you can The most important safety measure you can include in your lab is the proper selection of include in your lab is the proper selection of eyewear. Always double check with the eyewear. Always double check with the manufacturer for their suggested eyewear manufacturer for their suggested eyewear requirements. Look for the wavelengths and requirements. Look for the wavelengths and Optical Density(OD) values stamped on the side Optical Density(OD) values stamped on the side of the eyewear, does it match the wavelengths of the eyewear, does it match the wavelengths of the equipment you are using? of the equipment you are using? 

32

Lasers Cont.

Analysis of laser accident data involving Analysis of laser accident data involving 272 accidents reported to Rockwell 272 accidents reported to Rockwell Laser Industries from 1964 to 1994 Laser Industries from 1964 to 1994 reveals that reveals that eye injury was the most commonly reported laser eye injury was the most commonly reported laser

related accident related accident eye injury was involved in slightly over 74% of all of eye injury was involved in slightly over 74% of all of

the accidents recordedthe accidents recorded over 90% of the eye injury cases recorded some over 90% of the eye injury cases recorded some

functional loss, of which 77% was permanentfunctional loss, of which 77% was permanent

33

Lasers Cont.

The most common cause of accidents The most common cause of accidents was accidental eye exposure during was accidental eye exposure during beam alignmentbeam alignment

The second most common cause of The second most common cause of laser accidents resulted from misaligned laser accidents resulted from misaligned opticsoptics

The third most common cause of The third most common cause of accidents was failure to wear available accidents was failure to wear available eye protection. eye protection.

34

Lasers Cont.

Statistical data gathered by LIA concludes that Statistical data gathered by LIA concludes that the most common laser incidents are caused the most common laser incidents are caused by Nd:Yag (29.7%) and Argon (20.5%) lasers. by Nd:Yag (29.7%) and Argon (20.5%) lasers.

More importantly are the occupations which More importantly are the occupations which are involved. are involved. Out of 12 categories, scientists are involved in 17.6% Out of 12 categories, scientists are involved in 17.6%

of laser incidents, second only to technicians of laser incidents, second only to technicians (21.3%). (21.3%).

Doctors and Nurses include 9.2% of all incidents, 5Doctors and Nurses include 9.2% of all incidents, 5thth highest of all categories.highest of all categories.

35

Lasers Cont.

What are the causes?What are the causes?

1.1. Unanticipated eye exposure during Unanticipated eye exposure during improper alignment procedures. improper alignment procedures.

1.1. Available eye protection is not often used. Available eye protection is not often used.

1.1. Improper methods of handling high voltage Improper methods of handling high voltage lead to severe shock and even death. lead to severe shock and even death.

36

Lasers Cont.

4.4. Protection for non-beam hazards is Protection for non-beam hazards is often lacking. often lacking.

5.5. Improper restoration of equipment Improper restoration of equipment following service. following service.

6.6. Incorrect eyewear selection and/or Incorrect eyewear selection and/or eyewear failure. eyewear failure.

7.7. Equipment malfunction. Equipment malfunction.

37

Lasers Cont.

It only takes 0.25 seconds(time required It only takes 0.25 seconds(time required for the blink response) with a direct hit for the blink response) with a direct hit from a high powered laser to damage from a high powered laser to damage your eyesight. your eyesight.

Don’t become a statistic, protect your Don’t become a statistic, protect your eyeseyes