title: Class I
text: # Class I
  
  Class I may refer to:
  
  * Class I antiarrhythmic
  * Class I electrical appliance, a device constructed according to electrical grounding specifications in the IEC 60536-2 standard
  * Class I bacteriocin, a type of toxin produced by some bacteria
  * Class I biosafety cabinet
  * Class I laser, a type of eye-safe laser defined in the ANSI Z136 standard
  * Class I rail carrier, a type of major freight railroad company in Canada
  * Class I railroad, a type of major freight railroad company in the United States
  