Big tax breaks for companies not known for their eco-friendliness have wormed their way into a tax bill that has passed the House and another tax bill that is under consideration in the Senate. Enviro and consumer groups are criticizing tax breaks for the timber industry, oil and gas companies, and nuclear power plants. A provision in the House bill related to utility mergers would save the utility industry more than $1 billion over the next 10 years by exempting utilities from paying taxes on a fund for shutting down nuclear power plants. Pres. Clinton is unlikely to approve the Republican tax plan unless it is significantly scaled down.