LONDON—OPEC is encouraging its members to engage with the U.S. administration over a proposed U.S. bill against the group, known as NOPEC, and to explain that passing the bill could put at risk U.S. interests abroad.

A U.S. House panel passed a bill this week to open OPEC to lawsuits for collusion in boosting oil prices but it is uncertain whether the full chamber will consider the legislation.

“It is essential that member countries reinforce diplomatic bilateral contacts with government officials in the U.S. ... and explain the disadvantages for the U.S. should the NOPEC bill become law,” according to a letter written by OPEC Secretary General Mohammad Barkindo to member states and seen by Reuters.

“These disadvantages might include: weakening the immunity principle at a global level, putting at risk U.S. interests overseas, and the protection for their personnel and assets,” the letter said.

Similar bills to target OPEC when oil prices rise have appeared in Congress over the past two decades without success.

Barkindo said “several prominent U.S. economic actors” had expressed reservations about the NOPEC bill, including the U.S. Chamber of Commerce.

His letter to OPEC members included a letter from Neil Bradley, the chamber's chief policy officer, addressed to U.S. House of Representatives Judiciary Committee Chairman Jerrold Nadler (D-N.Y.) and Jim Jordan (R-Ohio), a committee ranking member.

“Under reciprocal legal regimes the United States and its agents throughout the world could be tried before foreign courts—perhaps including the military—for any activity that the foreign state wishes to make an offense,” Bradley wrote in the letter dated April 13.

Risk to Market

Barkindo said other disadvantages of the bill might include undermining important trade and energy relations between the United States and member states and might affect oil prices.

It could “increase the risk of volatility of the international oil markets, which directly affects U.S. oil-producing states and corporations,” he said.

The NOPEC bill, introduced by Rep. Steve Chabot (R-Ohio), was passed by voice vote in the House Judiciary Committee.

Letters from OPEC’s secretariat to members are fairly common and relate to events that may impact energy consumers and producers.

Barkindo’s letter said the bill could lead to fines on OPEC members and its national oil companies, which could be collected through seizure of assets on U.S. territory or elsewhere.

It said the Vienna-based secretariat would resume monthly reports on the bill’s progress, call a legal team meeting to brainstorm possible actions and gain a better understanding of the new U.S. administration’s position on the bill.