A product can be harmful to society because (a) its production causes harm; (b) the production of production resources causes harm; and (c) the use and disposal of the product cause harm. In textbook models of the harm caused in production, the sum of the costs of harm (of e.g. emissions) and of prevention is minimized in order to determine the optimal level of harm. Various instruments, such as green taxes, environmental liability and allowances might be applied. It But to obtain the optimal use of these tools, governments will need about the same amount of information for each of them. A notable exception is cap-and-trade. If lack of information puts optimality out of reach, cost benefit analyses, based on obtainable information, can be used. When it comes to the harm caused by the production of inputs and by the use and disposal of the product, the government will generally be the “cheaper information gatherer”. If governments use the tools such that the cost of harm is reflected in the prices of inputs and outputs, it will be in the interest of producers to optimize production methods.