I'm feeling lazy, so I'll try to make this point concisely.
In 1984 forty tons of methyl isocyanate was accidentally leaked from a Union Carbide plant in Bhopal, India which resulted in the death of tens of thousands of people and the injury of hundreds of thousands. The accident was the result of gross negligence on the part of the plant, having failed to take virtually any necessary safety precautions. Yet little in the way of compensation has reached the victims of this travesty; additionally, Bhopal is still contaminated.
The Bhopal disaster is what could happen in the United States if the safety and environmental regulations that we have were not in place.
Union Carbide, which contributed to Bush's campaign funds, would indeed like to be deregulated. And when Bush became President, one of the first things he did was to ask polluting industries which rules they would like to not follow, and then to proceed to try and eliminate or roll-back those rules.
Do you think this is fear-mongering on my part? If so, then read this.