Apple Computer has prepared this document to help answer questions about ozone emissions from laser printers. We have used information from the American Conference of Governmental Industrial Hygienists (ACGIH), the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Underwriters Laboratory (UL). For additional assistance please contact an authorized Apple reseller or call Apple Customer Relations at 1-800-776-2333. To locate an Apple reseller in your area, call 1-800-538-9696.
Background Information
Ozone gas is emitted in detectable levels by some laser printers and photocopiers as a byproduct of the electrophotographic process. In laser printers the primary source of ozone is the corona wire which produces an electrical discharge to make the toner powder temporarily adhere to the print drum.
Ozone is produced only when the printer is printing. The current OSHA permissible exposure limit for ozone is 0.1 parts of ozone per million parts of air (ppm) averaged over an 8-hour work shift.
Manufacturers install special filters to ensure safe ozone emission levels. Laser printers that operate without a corona wire emit a negligible amount of ozone gas and do not require these filters. In the US, UL provides an ozone emission standard based on OSHA exposure limits. In Europe, the maximum permitted ozone concentration is specified by European Norm (EN).
A properly maintained laser printer that is installed in a well-ventilated area should not expose users to unsafe ozone levels. In general, filter effectiveness can diminish in direct proportion to the number of pages printed. Therefore, filters should be replaced periodically. Dust accumulating on the filter's surface can also affect its performance.
Ozone can be a mild to severe irritant (dry throat and nose, headache, and sore eyes) and at very high concentrations can have serious adverse health effects such as nausea and pulmonary congestion.
Ozone (O3) is a highly unstable molecule that reverts quickly to oxygen (O2). Ozone concentrations may rise to noticeable levels depending on the rate generated (amount and time) as well as the physical environment (such as room ventilation and location of workers).
Typically, ozone can be identified by its characteristic odor at concentrations below the permissible exposure limit. However, as the concentration of ozone or the duration of exposure increases, the ability of a person to smell it may decrease.
Apple's LaserWriter Printers
Apple is committed to making products that meet or exceed the industry and government health and safety guidelines of every country where we do business. All Apple laser printers are within the limits of the UL guidelines when shipped from the factory to the customer. The technology is advancing, however, and most new laser printers have no corona wire and do not emit ozone.
Of Apple's printer products, only the Color LaserWriter 12/600 PS and the Color LaserWriter 12/660 PS have corona wires. These printers have ozone filters that are designed to operate effectively for printing up to 100,000 pages. For maximum effectiveness, Apple recommends service (checking the entire ozone emission control system) and an ozone filter replacement after 50,000 pages. You can print a startup page to determine your laser printer's page count. Dusty conditions or damage to the filter may necessitate more frequent filter replacement. This maintenance check and filter replacement can be done by any authorized Apple service provider.
The laser printer works best in relative humidity between 30 and 70 percent. Lower humidity can slow the natural breakdown of ozone in the air and can reduce the filter's effectiveness.
Proper installation of your laser printer will help to keep the ozone concentrations at a safe level. Choose a well-ventilated area. In general, a correctly designed air-conditioning system provides adequate ventilation for printer use. Air circulation is especially important if there are multiple laser printers and/or photocopy machines in an area. A small, enclosed space such as a closet should not be used for printing. Placement in a common area is preferable to placement in an individual's workspace. The fan exhaust should not blow directly in anyone's face.
None of Apple's other printers emit ozone. The ImageWriter II; Color StyleWriter 1500, 2200, 2400, 2500 & Pro, and Apple StyleWriter 1200 are not laser printers and do not emit ozone. The Personal LaserWriter 300 & 320; LaserWriter 4/600 PS, 16/600 PS & 12/640 PS; and LaserWriter Select 360 do not have a corona wire and therefore do not require an ozone filter in order to meet UL safety requirements.