Click here to view a PDF write-up of the incident.
An academic department turned over two green laser presenters labeled “Class 2″ to the Homewood Laser Safety Advocate for evaluation because one seemed “too bright.” Normally, a Class 2 laser presentation pointer should put out no more than 1 milliwatt of energy.
Both presenters were found to be putting out more than 10 times the allowable amount of energy, including energy in the invisible infrared range, which is more dangerous. (Green laser pointers are actually infrared lasers that use special optics to generate green light from the IR.) The Laser Safety Advocate tested several additional pointers from that department, finding them all in conformance with their markings. The overpowered pointers were disposed.
The overpowered pointers were actually hazardous Class 3B lasers which should not be used in an uncontrolled lecture or presentation setting. Homewood limits the power of laser pointers to Class 2; testing has shown that brighter pointers are not necessary in any lecture hall on campus. The class of a laser device is stamped on a small yellow or white sticker on the product.
These were name-brand laser pointers purchased from nonstandard sources (e.g., online auction sites); we are as yet unsure whether they were genuine branded products that are off-specification or if they were counterfeit. Please buy all laser pointers from standard JHU-approved sources such as Office Depot; unusual distribution channels are more likely to sell counterfeit or otherwise out-of-specification products. A sample of the sample laser presenter purchased from a JHU-preferred vendor measured within normal safe tolerances.
In 2013, the National Institute of Standards and Technology (NIST) found that 90% of green laser pointers and 44% of red laser pointers were out of compliance with federal safety regulations and their markings.
If you have a laser pointer that seems too bright, especially if it is green, contact the Homewood Laser Safety Advocate, Niel Leon, [email protected]. He can test your laser pointer and return it to you if it is safe to use (or help you find a source for a safe one if it’s not).
See the HSE Guidance Document on laser pointers, as well as this fact sheet(Laser pointer fact sheet v9-170725FNL), for more details.