| Clean Air and Water (quality) | Clean Air and Water (quality) | 665 |
| Energy/Nuclear | Energy/Nuclear | 362 |
| Environment/Superfund | Environment/Superfund | 134 |
| Natural Resources | Natural Resources | 93 |
| Chemicals/Chemical Industry | Chemicals/Chemical Industry | 91 |
| Fuel/Gas/Oil | Fuel/Gas/Oil | 66 |
| Health Issues | Health Issues | 65 |
| Utilities | Utilities | 51 |
| Trade (domestic/foreign) | Trade (domestic/foreign) | 33 |
| Food Industry (safety, labeling, etc.) | Food Industry (safety, labeling, etc.) | 29 |
| Taxation/Internal Revenue Code | Taxation/Internal Revenue Code | 25 |
| Waste (hazardous/solid/interstate/nuclear) | Waste (hazardous/solid/interstate/nuclear) | 24 |
| Budget/Appropriations | Budget/Appropriations | 18 |
| Agriculture | Agriculture | 14 |
| Animals | Animals | 11 |
| Veterans | Veterans | 11 |
| Financial Institutions/Investments/Securities | Financial Institutions/Investments/Securities | 7 |
| Real Estate/Land Use/Conservation | Real Estate/Land Use/Conservation | 7 |
| Government Issues | Government Issues | 5 |
| Science/Technology | Science/Technology | 4 |