HALIFAX -- Nova Scotia's top health official has revoked a special exemption for workers at Halifax-based Irving Shipbuilding that allowed them to travel to and from the United States during the pandemic.

Dr. Robert Strang, chief medical officer of health, issued a statement Wednesday saying questions and concerns have been raised about the exception granted in June by the province's public health department.

He said "very tight restrictions" were placed on the exemption, which he approved. He did not offer details about the nature of the concerns that were raised.

Strang, however, made it clear there will be no further company travel to or from the United States while the border between the two countries remains officially closed for non-essential visits.

He also said he has ordered some Irving employees to isolate themselves at home for 14 days and submit to COVID-19 testing.

This report by The Canadian Press was first published June 8, 2020.