German industrial gases group Linde’s supervisory board is due to vote on a merger agreement with U.S. peer Praxair on June 1, two people close to the matter told Reuters.

The companies said that they had reached a deal in principle on a Business Combination Agreement for the proposed $70 billion merger, but some unanswered questions will be addressed at Thursday’s meeting, one of the sources said without elaborating.

Linde declined to comment on the matter.

The all-share merger of equals, intended to create a market leader that will overtake France’s Air Liquide , had fallen behind schedule because of the complexity of talks to forge a formal agreement.

Labor representatives at Linde fiercely oppose the merger, mainly because plans to move the headquarters outside Germany would dilute their influence, which currently gives them an effective veto over strategic decisions.

The first source told Reuters that the supervisory board members’ positions had not changed but that a final decision is expected nonetheless.