The greatest natural resource in a four-state area, Lake Michigan's safe keeping has increasingly become the center of concern and controversy.

Many are asking questions. Is the lake safe for recreation? Is drinking water drawn by numerous communities pure?

Is pollution lessening? Who are the polluters?

And most of all, what is being done to safeguard the lake?

Over eight months, The Times and nwi.com investigated. Reporter Christine Kraly traveled throughout the Lake Michigan basin, meeting with environmentalists, industry and government officials and talking with "plain folks who live and work along the lake." Thousands of records were reviewed and numerous interviews conducted.

Among the key findings:

* Though the largest amount of pollutants entering the lake come from Northwest Indiana, industry in Wisconsin and Michigan are major contributors.

* Streams emptying into the lake, such as the Fox River in Wisconsin, are carriers of pollution.

* Other states are more lax than Indiana in imposing fines or taking remedial action against polluting violators.

* Chicago's municipal wastewater system fails to fully treat some discharges reaching the lake, waste that is not required to meet as stringent pollution regulations as some Northwest Indiana industries.

* Professional testing of the tap water in area communities proves it to be safe to drink.

* Indiana is not the only Lake Michigan state to have had a backlog in reviewing expired environmental permits.

* The lake is safe for recreation.

In all, the investigation shows efforts to protect the lake are intense but complicated as industry and the environment face off.

See: http://nwi.com/special/water/