David L. Shenkenberg, Features Editor, firstname.lastname@example.org
Writing in an online forum, “Franz” confides that he injured his eye when installing an infrared laser for a customer. It was only a Class 1M, 16-mW laser, but he looked at it through a telescope that amplified the signal.
“Fortunately, my eye cured, and the symptoms I described … are gone,” he said in an e-mail. “The conclusion is clear, not to look into the laser beam through the telescope,” he added. However, not everyone is as fortunate as “Franz.”
Many lasers have the power not only to cause eye damage but also to burn skin, and those hazards are from only the laser beam itself. Glass tube explosions, chemical spills, harmful gases and fires are all hazards that can occur with lasers. Blue light can cause a chemical reaction in the retina that damages the eye, and ultraviolet light can cause cancer. Laser injuries have resulted in a dozen or so deaths, all from electrocution, in the approximately fifty years that they have been in use.
A small percentage of the laser accidents that occur actually get reported, experts say, but several databases do contain information about accidents. Rockwell Laser Industries of Cincinnati maintains a database of laser accidents that goes back to 1964 with the intention that these historical lessons can prevent accidents from occurring in the future. “The intelligent learn from their mistakes; the really intelligent learn from others’,” said Bill Ertle, president of the company.
Who has the most accidents? Is it the technicians who frequently service the lasers, or is it laser-wielding amateur enthusiasts? The Rockwell database shows that most accidents happen to scientists who become complacent. “[Lasers] are safe when they are used responsibly,” Ertle said.
Ertle holds leadership positions with the American National Standards Institute (ANSI), while safety consultant Roy Henderson of the UK is an International Electrical Commission (IEC) committee member. The ANSI board develops safety rules for the US, and IEC rules are used in Europe and Canada. Ertle and Henderson said that the rules in the US and overseas are similar.
In the US, OSHA enforces the ANSI standard and ultimately can shut down facilities that fail to comply with regulations. The FDA regulates all lasers as medical devices, even those not specifically intended for medical use.
Ertle and Henderson recommend restricting access to the laser beam as the first line of defense against injuries. In terms of basic safety, they suggest training, eyewear, barriers, signage and various safety devices.
Switzerland-based laser safety consultant Rüdiger Paschotta notes also that interlocks can prevent people from entering the laser room or firing the laser by accident, while black beam blocks or cubes can obstruct the beam. In materials processing, devices are needed to remove fumes or debris.
Getting employees to pay attention
Paschotta points out that managers of laser facilities sometimes establish rules that protect themselves legally but that are impractical for employees to implement. Consequently, employees may ignore those rules. Should managers crack the whip harder? Paschotta says no. “[Employee] feedback always needs to be taken seriously, and [employees] need to get convinced that the rules are there to protect them in reasonable ways, not just to protect some superiors,” he said.
Ertle and Henderson also recommended getting employees involved in developing safety protocols. They cited a case that they consulted on where management wondered why its employees avoided wearing safety glasses. It turned out that the employees had been assigned darkly tinted ones, and they were lifting the eyewear to be able to see what they were doing. The glasses were darker than necessary for the laser beam that was being used, so the Rockwell consultants recommended that the employees wear lighter eyewear, solving the problem.
Paschotta recommends a careful risk assessment before work begins, practical and convincing guidelines informing staff of the risks and ways to minimize those risks, enforcement of the guidelines and removing factors that could undermine the safety culture.
“The culture of the organization is very important,” Henderson added. Employees need to feel that they can discuss issues with their superiors.
Another way to get educated in laser safety is by attending the International Laser Safety Conference that the Laser Institute of America hosts each year. This year, it was held from March 23 to 26 in Reno, Nev. The event includes a practical application seminar and case studies on laser safety.
Amateurs gone wild
Lasers have been spreading outside the confines of well-regulated industries and into the hands of amateur enthusiasts. This year, police arrested a 24-year-old Seattle man in response to weeks of complaints that green and red lasers had been shined into the cockpits of pilots landing at Sea-Tac airport, a felony in Washington state. And in Russia in July 2008, lasers blinded almost 30 attendees of a popular type of party known as a rave.
In the US, the FDA regulates the marketing and importation of lasers. The federal agency states that it is illegal to market lasers with output powers greater than 5 mW as laser pointers or demonstration products. In 2006, the agency sent a warning letter to the headquarters of Wicked Lasers in Shanghai, China, and the agency has banned the importation of the lasers into the US.
Wicked Lasers has scored favorable press in Wired, Maxim, Fast Company and the New York Post, and the company even made it into the Guinness Book of World Records for the most powerful handheld laser. The company’s products were mentioned in Fast Company and Guinness in 2007, and the New York Post product write-up happened in 2008, well after the company received the FDA warning letter. The FDA did not respond to requests for comment on its current enforcement practices regarding Wicked Lasers.
A representative of Wicked Lasers wrote to Photonics Spectra, “We do not believe there are any licenses required for operating our lasers … It is the buyer’s responsibility to check your local laws before buying.”
Experts say that it is true that powerful lasers are not illegal for an individual person to own in the US if the laser is shipped without getting noticed by inspectors. The onus is on the manufacturer and not the user.
Wicked Lasers sells blue, red and green lasers to enthusiasts worldwide via its Web site, www.wickedlasers.com. Its most powerful handheld laser is the Spyder II GX, which is sold in powers ranging from 200 to 300 mW. The company also offers lab lasers with 1000-mW output. Its 4100-lm Torch flashlight “is capable of melting plastic, setting paper on fire within seconds and … frying an egg, or a marshmallow on a stick,” according to the company Web site at the time of this writing.
Rockwell Laser Industries’ President Bill Ertle said, “We have spoken directly to [Wicked Lasers], and they have decided to fight [because] they are making so much money hand over fist.” Jim Naugle, marketing director for the Laser Institute of America, said that he had gone to a laser show in Shanghai not long ago and “They’re just shining [the lasers] all over the place.”
The amateur arena extends to demonstrations on Web sites such as YouTube and instructables.com. Ertle said that he saw a video clip of a man developing eyewear on YouTube, but the man made several mistakes. “It was incorrect and downright scary,” he said.