The first reactor focuses the high-intensity sunlight onto the waste and is broken down into harmless chemicals.

This is a very simple experiment using a relatively harmless chemical with a sparkly, ashy reaction to a match.

Such a system could be used with microbial pesticides, Dr. Cuskey said, by applying the microbes along with a harmless chemical without which they cannot survive.

They prefer to build fences to keep them out or spray an offensive but harmless chemical on the plants.

Sludge generates several toxic gases, which are normally converted into harmless chemicals used in your 'ponics sections, when the environmental system is functioning smoothly.

In the basement of the house, two chemicals, harmless when separated, began to mix.

He acknowledged that pesticides were sometimes badly misused, but he also quoted an adage: "There are no harmless chemicals, only harmless use of chemicals."

The list said Iraq has a sophisticated binary system for delivering chemical weapons, in which two types of otherwise harmless chemicals are mixed to produce a lethal gas.

If only there were a harmless chemical that averted disease and helped prolong life.