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CRT's, lead poisoning and you
by Jon Zemanek

Most people currently only consider lead poisoning as a hazard for people living in older neighborhoods and homes with lead-based paint. However, with the geometric increase of computers and their subsequent retirement and disposal in recent years, lead poisoning is again becoming both an important health and environmental issue. How is lead again contaminating our communities? More importantly, why are computers to blame? The answer to both questions is the improper disposal of cathode ray tubes.

First of all, what is a cathode ray tube? Basically, cathode ray tubes, or CRTs, are the primary components of nearly every television and computer monitor. The CRT is pressurized glass tube with an electron gun in the back that shoots electrons onto a phosphorescent surface, which in turn creates an image on the opposite side of the glass. Below is a diagram of a basic CRT:

(Picture copyright: TechTarget, http://whatis.techtarget.com)

German scientist Karl Braun originally developed the CRT in 1897. In the first half of the twentieth century, it went through several modifications, eventually gaining the ability to receive and translate radio waves, making the television we know and use today. As researchers and scientists began developing computers during and after World War II, modified versions of the television were used to display data and provide visual interfaces for these devices.

So what is the big deal? One of the major ingredients in a CRT is lead. Lead is used in the phosphorescent coating of the tube and the metal is fused between two pieces of glass, making a complete and unbroken CRT relatively safe. When they are disposed of as trash, however CRTs are commonly crushed or burned. Crushing the glass releases solid lead into the soil and water, while incineration releases it into the air.

Lead is a deadly contaminant to humans, especially fetuses, infants and children. Poisoning (even in small doses) can severely hinder the physical and mental development of children. Higher amounts of lead can cause severe brain and kidney damage in adults and children (United States Environmental Protection Agency). Poisoning can occur in several different ways including ingestion of contaminated water, soil or food, absorption through the skin and the inhalation of contaminated air.

The National Safety Council estimates that in 2003, more 63 million computer systems will be retired and disposed. Virtually every system will have a monitor with a CRT. A typical computer monitor contains between three and four pounds of lead. If you do the math, it equates to approximately 94,000 tons of lead entering the environment, not counting other sources of lead pollution.

Controlling the amount of lead in our ecosystem can only be done through responsible and ethical actions of citizens, businesses and governments. Service-learning students can help by educating these groups about their responsibilities. They can start with the EPA's current list of approved recyclers in Pennsylvania who will properly dispose of CRTs at http://www.dep.state.pa.us/dep/deputate/airwaste/wm/
hhw/electronics/recyclers_list.htm.