If 2017 didn’t already seem fraught, the US government has decided to lift a ban on the production of lethal viruses. The decision comes just three years after the decision to prohibit the intentional creation of deadly pathogens was instituted and scientists will now be allowed to modify and grow new strains of viruses as long as they get permission first.

The lifting of the ban is conditional upon researchers having their plans reviewed and approved by a government panel prior to actually crafting the germs, meaning that scientists will have to explain why they should be allowed to do so and what potential benefit the research could provide for mankind.

As the New York Times notes, the ban was initially put in place after a string of incidents involving the production of pathogens that caused serious public outcry. Researchers in both the United States and the Netherlands announced that they had been attempting to mutate a deadly strain of “bird flu” and soon after a separate, but equally scary situation arose when a live flu virus was shipped between labs by mistake.

With those troubling episodes in the rear view, the National Institutes of Health has decided to lift this mandatory across-the-board ban for the purposes of continuing research into virus mutations and the potential to create even better vaccines. In presenting their requests to a panel of experts, scientists hoping to be granted permission to grow these deadly strains will need to offer a convincing argument as to why the potential advancements outweigh the risks.

Of course, some in the scientific community are fiercely opposed to the lifting of the ban. Many argue that creating new mutations of already deadly diseases can only end badly and fear an unstoppable pandemic may result.