A lot of modern materials are rather hazardous, and even in "small" quantities. The recent incidents in the news have demonstrated such. Clearly, it's important to make sure everyone follows the same rules. Said rules make sure that materials/substances are handled in a way that minimizes risk of such hazards being introduced to environments they are harmful to, whether that be where we are settled, or the surrounding landscapes that we often trek. The economic impacts of hazardous spills or incidents are long term costs, and high ones. Pinning those on the one's responsible, the businesses that failed, is also an administrative cost that doesn't seem to be considered often enough. Keeping regulations saves the government the work of exacting justice, and keeps our citizens safer.

Additionally, adjusting rules to not affect all corporate entities leaves a rather concernable loophole of using many small businesses to stay under the safety regulations, in which these corporations would be the same in all but name. They would have the same impact as a large business but somehow still be legal, defeating the point of repealing the current regulations. Companies have already demonstrated in many cases that they can, and will, do such things to cut costs, and the costs of such activities will be left on us, unfairly.

Understand that whatever benefits one thinks they see currently by deregulation of this extent in industry, they will be cost far more in the future.