The pesticides are banned in the United States, but sold by American companies abroad.

The bananas are sprayed from the air. Then we see the bananas stuffed in pesticide-coated bags, and hear workers saying that the pesticides make them sick. We see the green bananas being doused a third time, sprayed directly one last time before the company label goes on.

Finally we see a mother and baby in an American supermarket. The mother picks up a bunch of bananas. The baby takes one and puts the pesticide-dosed skin in his mouth.

This is the "circle of poison" -- American chemicals, banned in the United States, sold and used abroad, coming back to us as coatings on our food.

Two strong documentaries telling the story of unsafe pesticides and medicines that are sold to the world anyway begin the fourth season of the Non-Fiction Television series tonight at 9 on Channel 26 (with pesticides) and Wednesday night (with medicines).

In the first of the two parts, on pesticides, the film opens with the information that representatives of the industry -- five companies and the national trade association of pesticide manufacturers -- refused to be interviewed.

"At least 200 million pounds a year of pesticides exported from the United States are totally prohibited, severely restricted or never registered for use in our country," says the narrator. There is no comment from the exporters.

"If people around the world don't believe that American products are safe," says Rep. Michael D. Barnes (D-Md.), "and if we get a reputation around the world for dumping our banned products on other countries, that's not going to help U.S. trade, help American business sell overseas." No comment from exporters.

Dr. Roberto Chediak, a physician working for a group of Central American universities, says, "The freeness with which they advertise and sell pesticides in Central America has reached a catastrophic level . . . Officially in Central America they refer to 5,000 cases of pesticide poisoning, but we believe this is really lower than the actual amount . . . For example, in Costa Rica, they say there are 1,500 cases in five years. We looked at a couple of hospitals and found that in three months alone there were 700 cases of poisoning, just in those three months . . . " No comment.

Says Jose Lutzenberger, a Brazilian environmentalist, "Just recently we had a tremendous scandal when it was officially recognized that most of our tomatoes were being treated with mercury compounds . . . all our tomatoes on the market were contaminated with mercury. It's well known that mercury is a nerve poison . . . The big international outfits that produce and sell these products know what's happening. And they know that in the case of tomatoes, for instance, where mercury compounds are even against the law, they know they are selling it where it is being used against the law, and they insist on selling it." No comment from the big international outfits.

The film on medicines to be aired Wednesday night is even stronger in its emotional impact. Also, it turns out to be a far better piece of journalism because the industry was willing to comment. This kept producer-reporter Robert Richter more honest, and thus in the end, more convincing in driving toward his point.

For example, in the pesticide film, several very large questions which might have damaged Richter's point could be ignored, probably because the industry was not there to raise them. Those "pesticide poisonings" -- do they not occur from approved pesticides ingested in quantity as well as banned ones? How many of those poisonings were confirmed by strict medical evidence and not simply accepted because workers made the connection anecdotally? There are a dozen more unanswered questions that suggest some sloppy work.

The suffering and death caused by unsafe medicines are more certain and more affecting because we hear that the case is not quite so clear-cut, because we see a manufacturer giving a lame excuse through a protective blanket of bureaucratic language: "It is a question of lack of implementation of . . . policy."

If ever you wanted to know how human beings behave in the absence of rules, in an open, unregulated market, these films provide the answer. Let us buyers be wary of "regulatory relief."

At the end of the Carter administration an executive order was signed that attempted to regulate the export of unsafe products. "When President Reagan came into office he immediately rescinded the executive order," says Rep. Barnes in the film. "Shortly after that, we held hearings to find out what the new administration's posture was going to be. They refused to send a witness up."