The law allows Nasa to apply for a waiver against the ban in special circumstances, but any appeal would have been rejected under a moratorium that has been introduced by the agency's administrator, Charles Bolden.
In a separate development, the UK's National Farmers Union (NFU) has applied for an "emergency" lifting of the moratorium for some oilseed rape to deal with a pest beetle, but campaigners say rape yields have actually increased since the neonicotinoid ban.
They applied for an exemption, spelled out in the moratorium policy, that allows for continuing work "urgently necessary to protect the public health".
Dench says it can be particularly tricky because as long as a moratorium is place, most on the list can get work permits, but can't apply for permanent residency.
Mr Johnson announced the lifting of a moratorium on applications for university titles, though universities will still have to wait until after the new consultation to apply for degree-awarding powers.
A controversial accompanying editorial called for a moratorium on PAC use in the absence of such data [ 4].
There have even been calls for a moratorium on its use until the issue is settled [ 13, 14].
The Connors et al. study [ 25] has influenced several reviews on the worth of pulmonary artery catheterization and calls for a moratorium on the use of PACs.
Not surprisingly, there has been a call for a moratorium on the clinical use of intravitreal infliximab outside of well-designed trials [ 86].
Environmentalists called for a moratorium or ban on the use of genetically engineered corn.
