Milton Marks, a Democratic state senator representing San Rafael in Northern California, in the next two weeks will lead a trade mission to Indonesia to scout opportunities in an estimated $100 million market for environmental products and services.

The mission is designed mainly for small and medium-sized companies."Indonesia has recently enacted environmental standards, set cleanup goals and has an agency for enforcement. It's one of the most rapidly growing industrial economies in the world and holds a lot of potential for California companies," said Joy Skalbeck, an assistant to Sen. Marks and a consultant for the state Senate Maritime Committee.

Prime opportunities are said to exist in supplying water pollution control equipment, air pollution control equipment, sludge management and solid waste control equipment and industrial waste control equipment.

Services of immediate need most likely include assistance in preparing environmental impact reports and environmental impact statements, as well as in developing compliance policies and procedures, said Will Harris, head of Pan Pacific Environmental Services in San Francisco, a design and engineering consultancy firm.

Indonesia in 1990 created a central authority in Jakarta to coordinate environmental regulations. Monitoring and enforcement procedures are carried out at the provincial level.

The country's most pressing environmental concern is said to be water quality and water availability. Rapid growth and urban migration have strained water sources, while uninterrupted dumping of untreated industrial and municipal waste has damaged water quality.

The government also wants to enhance the ability of public and private institutions in developing environmental impact assessments. Such assessments are now required for all new projects and for existing facilities that produce toxic or hazardous waste.

Furthermore, as Indonesia looks to cut down on air pollution, it will likely turn to alternative forms of energy.

"I've talked to a lot of people who have said they are starved for electricity over there," said Ron Svendsgaard, president of the Northern California Co- Generation Association, which has some 100 energy firms as members.

"If that is the case, there is a lot of opportunity, for smaller power plants, which is essentially what co-generation is," said Mr. Svendsgaard, who plans to participate in the trade mission.

Other areas of concern include the reversal of environmental degradation, sewage regulation and remediating the impacts of small-scale industrial activities.