New shine in the `rust belt'. Revived steelmakers are just one sign of brighter days ahead. After years of industrial decline, Northwest Indiana is making a comeback. Businesses and workers see fresh opportunities.

IN a helicopter 800 feet above Lake Michigan, Carl Manofsky points out a string of industrial buildings along the shore. His message: Northwest Indiana is roaring back to life. ``I think we're at the apex of activity,'' says Mr. Manofsky, a commercial real estate broker with Coldwell Banker. The region's steel plants are running full tilt. New businesses are moving into abandoned factories, unemployment is falling, and a robust optimism pervades the place.

``We still have a lot of work to do,'' says Thomas Barnes, Gary's new mayor. But ``there are a lot of real positive indicators and actions that are occurring right now.''

Adds Indiana Lt. Gov. John Mutz: ``We feel very good about where that part of the state is going.''

The area's rejuvenation stems from the revival in steel, but it is now moving beyond that.

Since their severe losses in the early '80s, the five major steel companies in the region have poured more than $2 billion into capital improvements here.

``Northwest Indiana has fared better ... than other parts of the country,'' says Mark Tomasch, spokesman for LTV Steel. ``It happens to be the right place at the moment.''

Now, other companies are moving in and hiring.

For example, since Chicago Steel and Tinplate opened its doors in Gary in 1985, it has expanded from 36 people to a projected 150 workers by next year. Its president, Bruce Mannakee, is confident the new business will last.

``It's not a boom-or-bust type of economy,'' he says. ``It's a steadily improving chart.''

The metal-processing company has also benefited because instead of building its own space, it was able to move into a well-located plant that had gone unused for six years. The move is one example of a trend that is taking place throughout the area. Developers are snapping up abandoned manufacturing plants, upgrading them, then leasing them to tenants. In one case, a new steel transportation and warehousing company moved into a portion of a plant that had gone virtually unused for 35 years.

This activity is spreading beyond steel-related companies and beyond northwest Indiana. Last year, throughout the Chicago area, a record 24 million square feet of industrial space was sold or leased to new tenants.

``The Chicago [area] marketplace is the strongest it has ever been in terms of warehousing, manufacturing, and distribution,'' says Donald Shoemaker, principal partner of a firm that bought an abandoned auto-stamping plant in Gary in 1986. He has one tenant signed up and two other strong prospects, neither of which is a steel-related company. The company has since bought a huge tract of industrial and commercial land in Cicero, Ill., a Chicago suburb.

Even foreign investors are moving into the region.

``It is a fascinating place to do business,'' says John Gates Jr., president of Capital and Regional Properties Corporation. The company, an Anglo-American developer, bought an unused Gary plant in 1984, then filled it by attracting 15 companies to the area. One-third of them are foreign-owned. Last November, Mr. Gates's company bought another empty plant in East Chicago and has signed up four tenants.

This industrial rebound is beginning to make itself felt in the lives of northwest Indiana residents. Unemployment in Lake and Porter Counties has fallen from a high of 15.7 percent in 1982 and '83 to 9.5 percent last year. That figure remains substantially above the 6.2 percent national rate, partly because the steel companies are so efficient that they don't need as many workers. But the region's new industries are starting to pick up the slack.

``It looks promising,'' says Rogers Fletcher, who finally landed a full-time job last month at Chicago Steel and Tinplate. He had been working part-time as a data-entry clerk, despite his college training in mathematics.

The region's future depends in large part on what happens in the steel industry. Lieutenant Governor Mutz, who is running for governor this year, thinks the region should try to attract more non-steel business.

``I have to say the future lies in more diversification,'' he says. Two promising areas are lakeshore marinas and Gary's airport.

When East Chicago expanded its marina last summer, the new boating slips filled up so fast that the community is planning another major expansion this year, and Gary and Hammond are rushing to build their own marinas. Lake Michigan docking space is so precious that the new marinas are expected to attract boaters from other parts of the region as well.

The Gary airport situation is less clear. Several Indiana officials want to make the underused field Chicago's third regional airport. But political wrangling has kept the project on hold.

``Our biggest problem is an image,'' Gates says of the region's prospects. ``Everyone looks at this area as a declining `rust belt' area. [But] the thing that's so amazing is how quickly it's come back.''