Exhibit99.1

Nalco Holding Company and Subsidiaries SegmentInformation 2004 Results Reclassified to Conform with 2005Presentation

|                                      |  |                                |         |                               |  |                                    |         |                                  |  |                           |         |         |  |        |         |         |  |        |         |         |  |  |
|--------------------------------------|--|--------------------------------|---------|-------------------------------|--|------------------------------------|---------|----------------------------------|--|---------------------------|---------|---------|--|--------|---------|---------|--|--------|---------|---------|--|--|
| (dollarsin millions)                 |  | ThreeMonthsendedMarch 31, 2004 |         | ThreeMonthsendedJune 30, 2004 |  | ThreeMonthsendedSeptember 30, 2004 |         | ThreeMonthsendedDecember 31,2004 |  | YearendedDecember 31,2004 |
| Industrial and InstitutionalServices |  | $                              | 329.3   |                          |  | $                                  | 349.1   |                             |  | $                         | 354.0   |    |  | $      | 363.7   |    |  | $      | 1,396.1 |    |
| EnergyServices                       |  |                           | 194.2   |                          |  |                               | 198.4   |                             |  |                      | 200.4   |    |  |   | 213.6   |    |  |   | 806.6   |    |
| PaperServices                        |  |                           | 164.1   |                          |  |                               | 161.2   |                             |  |                      | 164.6   |    |  |   | 173.0   |    |  |   | 662.9   |    |
| Other                                |  |                           | 25.7    |                          |  |                               | 31.7    |                             |  |                      | 55.2    |    |  |   | 55.1    |    |  |   | 167.7   |    |
| NetSales                             |  | $                              | 713.3   |                          |  | $                                  | 740.4   |                             |  | $                         | 774.2   |    |  | $      | 805.4   |    |  | $      | 3,033.3 |    |
|                                 |  |                           |    |                          |  |                               |    |                             |  |                      |    |    |  |   |    |    |  |   |    |    |
| Segmentdirectcontribution:           |  |                           |    |                          |  |                               |    |                             |  |                      |    |    |  |   |    |    |  |   |    |    |
| Industrialand InstitutionalServices  |  | $                              | 79.9    |                          |  | $                                  | 90.6    |                             |  | $                         | 88.2    |    |  | $      | 94.8    |    |  | $      | 353.5   |    |
| EnergyServices                       |  |                           | 44.3    |                          |  |                               | 44.0    |                             |  |                      | 42.1    |    |  |   | 43.1    |    |  |   | 173.5   |    |
| PaperServices                        |  |                           | 42.1    |                          |  |                               | 36.4    |                             |  |                      | 37.0    |    |  |   | 40.3    |    |  |   | 155.8   |    |
| Other                                |  |                           | (34.9   | )                        |  |                               | (13.5   | )                           |  |                      | (7.9    | )  |  |   | (21.8   | )  |  |   | (78.1   | )  |
| Totalsegment directcontribution      |  |                           | 131.4   |                          |  |                               | 157.5   |                             |  |                      | 159.4   |    |  |   | 156.4   |    |  |   | 604.7   |    |
|                                 |  |                           |    |                          |  |                               |    |                             |  |                      |    |    |  |   |    |    |  |   |    |    |
| Expensesnot allocated tosegments:    |  |                           |    |                          |  |                               |    |                             |  |                      |    |    |  |   |    |    |  |   |    |    |
| Administrativeexpenses               |  |                           | 45.8    |                          |  |                               | 50.9    |                             |  |                      | 41.7    |    |  |   | 50.6    |    |  |   | 189.0   |    |
| Amortizationof intangibleassets      |  |                           | 24.2    |                          |  |                               | 24.9    |                             |  |                      | 23.9    |    |  |   | 23.3    |    |  |   | 96.3    |    |
| In-processresearch anddevelopment    |  |                           | 122.3   |                          |  |                               | — |                             |  |                      | — |    |  |   | — |    |  |   | 122.3   |    |
| Businessoptimizationexpenses         |  |                           | — |                          |  |                               | — |                             |  |                      | — |    |  |   | 1.7     |    |  |   | 1.7     |    |
| Operatingearnings(loss)              |  |                           | (60.9   | )                        |  |                               | 81.7    |                             |  |                      | 93.8    |    |  |   | 80.8    |    |  |   | 195.4   |    |
| Otherincome (expense),net            |  |                           | (3.5    | )                        |  |                               | (1.8    | )                           |  |                      | (1.2    | )  |  |   | (50.5   | )  |  |   | (57.0   | )  |
| Interestincome                       |  |                           | 2.7     |                          |  |                               | 2.7     |                             |  |                      | 2.3     |    |  |   | 2.5     |    |  |   | 10.2    |    |
| Interestexpense                      |  |                           | (61.0   | )                        |  |                               | (62.7   | )                           |  |                      | (64.0   | )  |  |   | (63.1   | )  |  |   | (250.8  | )  |
| Earnings(loss) before incometaxes    |  | $                              | (122.7  | )                        |  | $                                  | 19.9    |                             |  | $                         | 30.9    |    |  | $      | (30.3   | )  |  | $      | (102.2  | )  |
|                                      |

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