<span>There are pros and cons as to whether CCA-treated (pressure-treated) wood should be removed from existing structures, and both sides are subjective.
Some of the arguments for leaving it include:
*When burned, the wood can release dangerous, and sometimes, lethal fumes.
*If buried in a landfill, the chemicals can soak into the ground and eventually contaminate ground water.
*Removing it can expose people to arsenic
*It is costly to remove an existing infrastructure that may or may not be harming people
*Studies conducted within the past decade have determined structures containing CCA-treated wood pose no hazard
*Studies also concluded that children who played on CCA-treated playgrounds were exposed to arsenic levels lower than those that naturally occur in drinking water
Some of the arguments for removing it include:
*The EPA determined that some children could face higher cancer risks from exposure to CCA-treated wood
*If removed, it will need to be disposed of and, as discussed above, that creates another set of problems that could affect a community's health.
A possible solution is to leave existing CCA-treated wood in place but seek viable, safe alternatives for future structures.</span>
Traditionally they include boron from group 3A, silicon and germanium in group 4A, aresnic and antimony in group 5A and tellurium from group 6A, although sometimes selenium, astatine, polonium and even bismuth have also been considered as metalloids. Typically metalloids are brittle and show a semi-metallic luster.
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine.
