Laser Safety Awareness

1. Laser Safety Awareness

2. Disclaimer • This training material presents very important information. • Your organization must do an evaluation of all exposures, applicable codes and regulations, and establish proper controls, training, and protective measures to effectively control exposures and assure compliance. • This program is neither a determination that the conditions and practices of your organization are safe nor a warranty that reliance upon this program will prevent accidents and losses or satisfy local, state or federal regulations. • All procedures and training, whether required by law or not, should be implemented and reviewed by safety and risk management professionals, and legal counsel to ensure that all local, state and federal requirements are satisfied.

3. Course Outline • Understanding Lasers • Optical Hazards • Optical Hazard - Exposure Limits • Optical Hazard - Measurements • Non-Optical Hazards • Laser Class, Hazards, and Controls • Engineering Controls • Administrative Controls • Summary

4. Understanding Lasers What is a laser? • “Laser" is an acronym for Light Amplification by Stimulated Emission of Radiation. • It is the amplification of high-intensity optical, infrared, or ultraviolet radiation produced as a result of stimulated emission that is maintained within a solid, liquid, or gaseous medium. It can be brought to a very fine and powerful focus. • It is a device that emits light as a stimulated emission of photons. Laser applications: • There are many types of lasers available for research, medical, industrial, and commercial uses.

5. Understanding Lasers How a laser works: • Electrons move in what is called the “lasing medium,” where energy increases from a ground state to an excited energy state, and then obtains spontaneous emission. • Spontaneous emission is the goal. It is achieved when electrons at the normal “ground state” have energy added, via electrical discharge, to “excite” them.

6. Understanding Lasers Lasing mediums: • Electrons move in the lasing media. • Lasing media can be solids, liquids or gases. • The type of medium dictates the wavelength of the laser beam. • Media can be manipulated to allow for tuning of the wavelength. • Wavelength is crucial in determining laser class and hazard.

7. Understanding Lasers Laser types: Lasers can be classified as operating in either continuous or pulsed modes. Each type has advantages for different applications. “Continuous Wave” lasers are also known as “Repetitive Pulsed” and their power output is continuous over time. “Pulsed” (also known as “Q-Switched”) lasers have their output in the form of pulses of light.

8. Understanding Lasers Laser type: “Continuous Wave” (also known as “Repetitive Pulsed”): • Emits a steady beam of light with constant amplitude and frequency. • Common uses: holography (optics), instrumentation, laser inspection, materials processing, forensics, entertainment, display.

9. Understanding Lasers Laser type: “Pulsed” (also known as “Q-Switched”): • Emits light in an off and on or pulsed manner. • It contains a shutter-like device that does not allow emission of laser light until it is opened. Energy builds up and is released by opening the shutter to produce a single intense laser pulse. • Commonly uses: Science and medical fields.

10. Laser Hazards The most common cause of laser-induced tissue damage is related to thermal effects and damage to the eye and skin. This would include erythema (sunburn), Skin Cancer, accelerated skin aging, increased pigmentation, Skin burn, photosenstive reactions Other effects include possible exposure to Radiation, Fire Hazards from more powerful lasers, exposure to compressed Gases or dyes

11. Optical Hazards Optical hazards depend on the geometry of the beam: • Direct beam: Light emerges with little divergence and alteration to its brightness. • Diverging beam: Light passes though an optical fiber or is focused by a lens and loses brightness. The hazard level is effected based on the angle of divergence and distance of the beam. • Reflected beam: Light passes thru a reflecting surface and the risks are dependent on the quality of that surface, e.g. smooth metallic surface causes a mirror type reflection. The brightness level (irradiance) depends on the type of beam and is the most important risk factor.

12. Optical Hazards Optical hazards and the eyes: • The location of injury in the eye; e.g., cornea, lens, or retina, is related to the laser wavelength. • Lasers must be labeled with the absorption wavelength and optical density (OD) rating at that wavelength. • Protective eyewear is required for Class IIIB and Class 4 lasers. • Personal Protective Equipment (PPE) is especially important in the laser alignment process. • Assure all staff follow the Hazard Assessment for the proper selection of PPE! For complete information, refer to the current version of the ANSI standard.

13. Skin and Optical Hazards UV radiation: • Ultraviolet radiation is hazardous to eyes and skin and can be emitted by laser discharge tubes and pumping tubes. • PPE is to be used. Commonly used PPE against UV are UV safety goggles and face shields, long-sleeved, tightly-woven clothing that covers the body, and gloves. • NOTE: Skin protection is not difficult because most clothing tends to absorb UV radiation.

14. Optical Hazards - Exposure Limits Maximum Permissible Exposure (MPE): • MPE is a measurement of the maximum level of laser radiation a human can be exposed to without experiencing long-term, adverse effects. • Three factors determine MPE: • Wavelength • Energy of the exposure • Duration of exposure MPE values for eyes and skin are listed in the current ANSI Standard.

15. Skin Hazards Thermal hazards and the skin: • Thermal effects are a major cause of tissue damage and are caused when heat is absorbed by tissue. The degree of effect depends on the amount of tissue exposed as well as wavelength, energy and time. Photochemical hazards and the skin: • Photochemical effects result from laser light and negatively impact cell chemistry thru the absorption of atoms and molecules, which can cause tissue damage.

16. Skin Hazards Thermal and photochemical effects and skin protection: • Skin burns can result from acute exposure to high power beams. • Skin cancer risk could result from prolonged exposure. • Use skin protection by covering exposed skin with lab coats, gloves, and an UV face shield. • Follow the PPE Hazard Assessment.

17. Optical Hazards – Exposure Limits Nominal Ocular Hazard Distance (NOHD): • NOHD is the distance along the axis of the direct laser beam to the human eye beyond which the MPE of the laser is not exceeded and viewing becomes safe at the operating power. Nominal Hazard Zone (NHZ): • NHZ is the zone inside which laser radiation exceeds the MPE for the laser. • Controlled access to the NHZ zone is required. • Outside of this zone, control measures are typically not needed. • Follow all established controls and PPE requirements set out in the Hazard Assessment.

18. Non Optical Hazards High voltage power hazards: • Electrical dangers are a significant risk. • Reduce hazards by enclosing high voltage sources and terminals. • Restrict the work area. • Turn off power before working on power supplies and follow lockout procedures! • Don’t create conductive situations by being grounded or wearing metal.

19. Non Optical Hazards Explosions: • Enclose pressure arc or lamps in housings that can withstand on explosion. • Do not bypass manufacturer safeguarding systems. Fire Risk: • Higher powered lasers such as a Class 4 beam can create a fire risk when the bean comes in contact with combustibles or flammables. • Terminate the beam with a non-combustible material. • Store flammable and combustible materials in proper containers and shield from the laser beam. Also remove them from the area if possible. • Have fire extinguisher equipment nearby.

20. Non Optical Hazards Compressed gases: • Many gases such as chlorine, fluorine, hydrogen chloride and hydrogen fluoride, are used in lasers. • Do not store incompatible chemicals together. Consult the Safety Data Sheet (SDS) for each chemical to determine chemical incompatibility and storage temperatures. • Ensure that cylinders are not free standing, and are stabilized and secure. • Carefully follow procedures for handling and storing cylinders.

21. Non Optical Hazards Laser dyes: • Laser dyes are organic compound solutions that form a lasing medium for dye lasers. • They can have a high level of toxicity. • Refer to each chemical’s SDS sheet for special handling instructions and PPE requirements. • Follow the PPE Hazard Assessment.

22. Non Optical Hazards Noise: • Safe noise level limits can be exceeded because of high voltage capacitor discharges. • Hearing protection (ear plugs or muffs) is an important protection in these cases. • Follow the PPE Hazard Assessment. Laser Generated Air Contaminants (LGAC): • Interacting Class 3 and 4 lasers can generate air contaminants or biohazards in medical applications. The severity of the hazard is variable depending on many factors, i.e. target material, gas, beam irradiance, etc. • Proper respiratory protection, ventilation, and other PPE must be determined in advance in accordance with a Hazard Assessment.

23. Laser Class and Hazards Laser classifications: • Lasers are often characterized by the duration of laser light emission. • Classification of lasers is extremely important in determining the appropriate hazard controls to make the laser system safe. • There are 4 classes of lasers.

24. Laser Class, Hazards, and Controls

25. Laser Class, Hazards, and Controls

26. Laser Class, Hazards, and Controls

27. Laser Class, Hazards, and Controls

28. Laser Class, Hazards, and Controls

29. Laser Class, Hazards, and Controls

30. Laser Class, Hazards, and Controls

31. Engineering Controls Overview: • Engineering controls have been developed with one specific purpose: To reduce the possibility of exposing people to hazardous laser radiation. • OSHA requires that engineering controls be the primary means of protecting the worker from the laser environment. • Required engineering controls should never be substituted without the express release of the Laser Safety Officer in charge.

32. Engineering Controls Protective housing: “Protective housing” is a physical barrier that will contain the beam and laser radiation from exiting the laser system so that Maximum Permissible Exposure (MPE) is not exceeded on the outside. • The housing should be clearly identified. • There should be a clearly marked switch to deactivate the laser. • Enclose as much of the beam path as possible. • When the beam needs to be adjusted then other physical barrier methods must be employed.

33. Engineering Controls • This sometimes occurs in the research phase or maintenance so that the beam can be manipulated. • Other control measures will have to be considered, e.g., Lockout, special training, restricting access to the area, curtain or beam stop barriers, and PPE. Laser use without protective housing: Follow the PPE Hazard Assessment.

34. Engineering Controls Protective interlocks: “Interlocks” are a mechanism which will automatically switch off the laser by blocking the beam, e.g. when the protective door is open. • The laser must be interlocked so it can’t operate when the housing is open. • Protective housings should be interlocked for Class 3 and Class 4 lasers. • Commercially manufactured lasers usually will have interlock systems built in.

35. Engineering Controls Laser access: • Ensure “Laser Use Registration” (LUR) is in place to ensure laser safety evaluation. • Restrict laser use to the immediate location. • Enclose whenever practical. • Use beam blocks to terminate beams, e.g. shutters, collimators, curtains, and other bean control devices are strongly encouraged. • Whenever the laser is in operation, access to laser facilities is restricted to laser users or persons being escorted by laser users. • Control access with locked doors (laser signs are not enough).

36. Engineering Controls Controlled areas: • “Laser controlled areas” are an area whose occupancy and activity are subject to control and supervision for the purpose of protection from hazards. • “Cordoned laser areas” are an area where there is a temporary laser hazard. It cordoned off by a temporary barrier, like a post and chain. • Determine NOHD and NHZ (see prior slide for definitions). • Label area to indicate the hazard.

37. Engineering Controls Controlled areas (continued): • Keep equipment in a laser controlled area. • Interlocked doors are required for Class IV area. • Provide laser safety eyewear for all personnel in the area. • Use indicator lights (laser powered) with three separate light colors to indicate: • When laser is powered. • When goggles are required. • When interlock is defeated and laser exposed, and enclosure can be opened.

38. Engineering Controls Barriers and enclosures: • “Barriers and enclosures” are used to prevent the beam from spreading outside the controlled area and exceeding the Maximum Permissible Exposure (MPE) level. • Typical barriers are laser curtains and partitions. • Rail curtains can be used to completely enclose the system. • Ensure the barrier material is not combustible, especially for Class 3 and 4 lasers. • Beam stops are designed to stop the beam path and are used behind optical devices if the beam becomes misaligned.

39. Administrative Controls Training: • Initial training is required. • Refresher training is recommended every two years. • Document all completed training. Inspection: • Inspection of all laser facilities is recommended annually. • Inspection should be completed following any equipment changes or corrective measures.

40. Administrative Controls Posting and Labeling: • All access points to the laser facility must be marked with ANSI standard laser hazard signs. • Laser enclosures must be labeled to alert users to laser hazards as per the ANSI standard. • Labels, signs and usage instructions can be acquired from Environmental Health Information Service (EHIS.gov).

41. Administrative Controls Medical surveillance: • For existing employees subjected to extended exposure. • Must establish a baseline with new employees. • Must identify preexisting conditions. • Must include skin exam. • Eye exams, including: ocular history, visual acuity, macular function, and ocular fundus via ophthalmoscope. • Termination exams required for workers leaving the job and company. Particularly necessary for Class IIIB and Class IV For Class IIIB & IV

42. Administrative Controls Incident Investigations (for accidents and near misses): • Report immediately to the laser Supervisor. • All “near miss” incidents must also be reported. • Laser Safety Officer must review all incidents. • Medical evaluation is required for affected employees who may have been exposed. • Root cause must be identified. • Corrective and preventive actions must be determined and implemented. Stop it from Happening Again! Identify Power Output Identify Type of Exposure Duration of Exposure

43. Summary • How a Laser Works: The movement of electrons and the impact of energy levels results in spontaneous emission. • Health Affects of Lasers: Eyes and skin are particularly vulnerable and are dependent upon the laser classification level, the operator’s use of PPE, and proper controls being in place. • Optical Hazards: These result from direct, divergent, or reflective laser light. Brightness is the key factor impacting health hazards. • Non-Optical Hazards: Ancillary hazards are bi-products of laser operation and require engineering controls for protection. • Laser Classifications: Four primary laser classifications and their associated hazards and controls have been outlined. • Appropriate Safety Controls: Awareness and utilization of all recommended engineering and administrative controls is required in order to proactively protect the worker.

44. Laser Safety Awareness Training This form documents that the training specified above was presented to the listed participants. By signing below, each participant acknowledges receiving this training. Organization: Trainer: Trainer’s Signature: Class Participants: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Name: Signature: Date: Remember to load your completed trainings into the Risk Management Center.