In 2015 Costain was removed from Pennsylvania Treasury's List of Scrutinized Companies Determined as Having Involvement In Iran after the company confirmed that neither it nor any of its subsidiaries have business activities in Iran.
In 2014, Costain was added to the Pennsylvania Treasury's List of Scrutinized Companies Determined as Having Involvement in Iran because of oil-related investment of US $20 million since 1996.
Firm/country[A]: Costain Oil, Gas & Process Ltd./United Kingdom;
Status: Gas refinery/processing plant at Bid Boland II;
Commercial activity: Expected completion 2009; Part of consortium whose contract is valued at $1.7 billion;
Firm comment: Contacted on January 14, 2010; no response as of March 22, 2010.
"In Iran, Costain led a consortium of four companies in the bidding and ultimate award by the National Iranian Gas Company of the Bid Boland II Gas Treatment Plant Project, valued at $1.67bn and financial negotiations are continuing." (Costain Company Press Release, June 2005)