The co-evolution of the ANSI Z136.1 standard for safe use of lasers and the underlying bioeffects data base

The ANSI Z136.1-2014 Standard for Safe Use of Lasers is the eighth revision of the guideline which was first issued in 1973 and subsequently updated in 1976, 1980, 1986, 1993, 2000, 2007 and 2014. The 1973 Maximum Permissible Exposure (MPE) guidance was based upon the best (but limited) laser induced injury threshold data available at that time. Laser bioeffects researchers have continued to develop new insights into the nature of laser/tissue interaction and to expand the laser-induced injury threshold database. The MPE guidance has evolved to accommodate the new data, though normally with some lag as the new data was assimilated and understood. The 2014 edition of the standard has caught up with the new data and understanding and has confronted the laser safety community with a greater number of changes with greater impact on the MPE guidance than had been introduced in any other edition of the standard. As the user community, has digested the new guidance, the impact on laser Classes, which are based on the MPE, has been questioned. This paper will compare the guidance of each the eight editions to the best laser-induced injury threshold data available at the time that edition was issued with the goal of understanding how the historic relationship between the threshold data and the MPE.