We have a slew of safety regulations that apply to, for example, chemical plants that handle substances every bit as dangerous as anything in a nuclear reactor. They basically work. They increase the operating cost a little bit. But they're not purposely designed to make the operation prohibitively expensive, so they don't.
Pricing externalities is a cost/benefit calculation, because overhead and inefficiency are externalized harms too. If you can prevent a 1 in 100 chance of a million dollar loss for $100 then you do it. If you have the "opportunity" to prevent a 1 in 10,000 chance of a million dollar loss for $10,000, you don't, because the expected cost of preventing the loss is more than it is to incur it. Unless you're trying to destroy something, and then you insist on it.
Pricing externalities is a cost/benefit calculation, because overhead and inefficiency are externalized harms too. If you can prevent a 1 in 100 chance of a million dollar loss for $100 then you do it. If you have the "opportunity" to prevent a 1 in 10,000 chance of a million dollar loss for $10,000, you don't, because the expected cost of preventing the loss is more than it is to incur it. Unless you're trying to destroy something, and then you insist on it.