Despite general acceptance that the manufacturing process for computers should be modified to reduce or eliminate the environmentally hazardous materials common in machines today, Intel predicts that it will be 2006 before the "healthy" PC will be a reality. The materials, such as lead and mercury, pose no health risks while the computer is in use, but when put in landfills, these materials can seep into groundwater or be introduced into the air if computers are incinerated. Intel cited the lack of alternatives to these materials as the primary reason the "clean" computer won't arrive soon. Lead solder, for example, is used throughout the circuitry. Although lead-free solders exist, they are considered inferior to lead solders. Many companies, including Intel and Sony, are working on developing environmentally friendly options for the manufacture of computers, but viable alternatives remain a long way off. CNET, 12 September 2002