At a gas station, you watch an attendant fill up a car's gas tank. The tank overflows. Gasoline spills onto the ground.

Gasoline and dry cleaning solvents that "smell funny" are important. They give us some of the things we want: clean clothes, and fuel to drive from place to place. But if dry cleaning solvents, gasoline, and thousands of other chemicals compounds are spilled, or stored or dumped improperly, they can become "hazardous wastes"

Something becomes a waste when it can not be recycled or used again. A hazardous waste is a waste that is either toxic (poisonous), can catch fire, corrode other materials or react with other chemicals.

Hazardous wastes can pollute the land. They can even pollute the water that is underneath, or next to, the polluted land.

Today we know better. At the old dumps and disposal sites across the United States, hazardous wastes could threaten public health and the environment.

And hazardous waste is not going to disappear. Every year, about 65,000 companies or company units make or transport more than 250 million metric tons of hazardous waste!

Americans want medicines, computers, cars, jewelry, insect sprays, paint and other products. So, what can we do about the hazardous wastes that come from making these products?

Beginning in 1990, it became illegal to get rid of most hazardous waste in land, unless land disposal of the waste is safe, or unless the waste has first been treated. Treatment can remove the hazards from hazardous waste. Scientists are studying different treatment methods to find out which ones work best. Possible treatments to destroy hazardous waste include incineration (burning), and using bacteria or chemicals.

But companies that don't create hazardous waste in the first place don't have to worry about how to treat it. With the land disposal ban now in place many companies are working hard to discover ways to create less hazardous waste.

Other companies are working on ways to recover hazardous materials and use them again. By changing a pollutant into a resource, a company can save money and protect the environment at the same time.

As for the old dumps and disposal sites where hazardous wastes have already done their damage, the country is working to clean them up. Have you ever seen newspaper pictures of people dressed in funny- looking rubber "space suites" poking long sticks into barrels? Those people are taking samples of the contents of the barrels. Their rubber suits help protect them in case the contents turn out to be dangerous. The samples they take will be studied in laboratories to find out exactly which hazardous substances or chemicals are inside the barrels. Then the contents will be disposed of safely.

Solid waste

Solid waste generally refers to the paper, aluminum cans/ glass jars, plastic bottles, spoiled food, broken TV sets, old stoves, junk cars and other trash and garbage that people throw away. Every year in the United States garbage trucks collect about 132 million tons of solid waste! What should we do with all of it?

• If we toss the stuff away carelessly, it litters streets, highways, the countryside and waterways,
• If we burn it in the open, it pollutes the air.
• If we leave it in the open at garbage dumps, it smells, looks ugly and attracts rats and insects.
• If we bury it, we lose the value of the materials in it that might be recycled.

To recycle solid waste and reclaim what is of value is an important goal. It is probably the best method of waste disposal because it allows material to be used again. Otherwise, solid waste is really wasted solids.

There are many reasons why we don't recycle and recover more solid waste today. We don't know how to recycle some wastes, such as certain plastics, And it often seems easier and cheaper just to throw things away. But the cost of hauling, disposing of and replacing throwaways is going up.

Some garbage that cannot be recycled or reclaimed now can be burned to produce energy. When burnable and nonburnable wastes are separated, the burnable waste can be mixed with coal and used as fuel in utility boilers.

Note in the picture how garbage can be collected and some of it burned to heat a building, while metal and glass that does not burn is recovered.

One way to reduce the solid waste problem is to produce less solid waste. Do we really need all the cellophane, cardboard, colored paper, metal foil and plastic bags that so many things come wrapped in?