Du Pont Co. said yesterday that it will take a lead role in investing more than $1 billion to commercialize production of an alternative to refrigerants that use ozone-depleting chlorofluorocarbons (CFCs).

In an attempt to get ahead of its competitors, Du Pont said it plans to build "world-scale" production facilities in Corpus Christi, Tex.; Louisville, Ky.; Dordrecht, Netherlands; and Chiba, Japan, to produce hydrofluorocarbon refrigerants for autos, appliances and commercial air conditioners. The plants would begin operating between 1992 and 1995, the company said.

The early and aggressive move by Du Pont into the vacuum that the worldwide phase-out of CFCs is creating may help give the chemical maker a leg up in marketing replacement products. Based on the plans of other chemical companies who are moving into the same market, Du Pont would be the largest manufacturer of products being developed in response to the phase out of CFCs.

The anouncement also demonstrates some of the difficulties of marketing an environmentally sensitive product.

Hydrofluorocarbons contain no chlorine and therefore have no effect on the ozone. However, environmentalists say they do contribute to global warming.

Du Pont announced in 1988 that it would end production of CFCs by the end of the decade. CFCs have been blamed for creating a hole in the ozone layer that protects the earth from harmful ultraviolet rays.

Du Pont made its announcement yesterday at an international meeting in London under the auspices of the United nations to discuss accelerating the timetable for a worldwide phase-out of the chemicals.

"There are large rewards for those companies that are economically prepared to develop the alternative products," said Leonard Bogner, an industry analyst with Prudential Bache.

"That's a big number, but we're not overly concerned at the costs of the projects or Du Pont's commitment because, at the other end of that cost, is a reward."

Du Pont's early announcement of its intent to provide the alternative chemicals could encourage automakers and others to move forward with the changes that would be necessary to use the new products.

On the other hand, Bogner and others said there is a risk that the Environmental Protection Agency may find problems with the various alternatives as it continues to test them.

EPA officials said that possibility was slight, and would not rule out all applications of the chemicals.

"Right now, we just don't have any red flags at all," said Reva Reubenstein, science adviser in the Office of Atmospheric and Indoor Programs.

One other danger that environmentalists warned of yesterday was that Du Pont's quick move to produce an alternative to CFCs could short-circuit development of other more environmentally beneficial alternatives.

"I think it is a very difficult public policy problem," said Alan Miller, executive director of the Center for Global Change at the University of Maryland.

"Obviously we do want to encourage industry to move out quickly as substitutes become available, but that doesn't mean that whatever they propose necessarily will be ideal nor will it receive the environmental seal of approval."

Joseph P. Glas, director of Du Pont's "Freon" Products Division, said the hydrofluorocarbons are relatively environmentally benign.

They "have a low global warming potential and, most importantly, they have a relatively short atmospheric lifespan," Glas said.