The National Academy of Sciences has released a controversial study that says 90 percent of grain-elevator explosions could be avoided if employes were trained better and the amount of grain dust in elevators reduced.

Nearly 200 deaths have been caused since 1960 because of grain elevator explosions, including five deaths in western Iowa three months ago.

Grain dust, which usually is stirred up when corn, wheat and other grains are moved from one place to another, is highly explosive. The report said explosions are caused most frequently when dust is ignited by sparks from machinery or by careless employes while welding.

The report was requested by the Occupational Safety and Health Administration, the Agriculture Department, and the National Institute for Occupational Safety and Health, for possible use in developing grain-elevator safety standards. Currently, there are no rules that apply specifically to grain elevators and mills.

The study drew criticism from the National Grain and Feed Association, which said its members have voluntarily complied with most of its recommendations.

Robert Harbrant, president of the AFL-CIO's food and beverage trades department, however, said the report proved the need for safety standards. Harbrant said dust from grain currently is removed at some grain elevators to satisfy Environmental Protection Agency regulations, but is later put back into the grain to boost its weight and price.