When a safeguard duty is imposed, less developed countries are excluded from the duties as long as their share of import volumes is less than 3% and as long as the sum of imports from all the less developed countries is below 9%. If small exporters begin stepping in and absorbing more than 3% market share because they face lower duties, they can be removed from the exemption list and see their duties increase to the level applied to everyone else.
This appears to have happened to Taiwan, which was originally exempted from the safeguard duties. Their removal from the exemption list means that steel imported from Taiwan will, effective 24 May, attract the safeguard duties of 10% (on top of the normal duties of 10%).
Although the regulations allow ITAC to raise these duties without an investigation, in the past they would still publish their proposal for comment before the decision was implemented.
Irrespective of what the regulations allow, an interesting technical question arises about whether or not interested parties were given a proper opportunity for their views on this matter to be heard before the decision was taken. This would include the Taiwanese government, who also may have something to say about the duties being extended to them without consultations.