WASHINGTON — After years of railing against the reams of regulations enacted during the Obama years, Republicans this week will zealously embark on an effort to roll back some of those rules using an obscure law known as the Congressional Review Act.

Republican leaders have dusted off this rarely used legislation, added to their tool kit in 1996, to quickly reject recently finalized Obama-era regulations, many of which they say impose an excessive burden on American businesses.

This week, the House is expected to use the Congressional Review Act to start the process of tossing out five rules, including one that limits the venting of methane, a powerful greenhouse gas, from oil- and gas-drilling facilities and another that requires federal contractors to report previous labor law violations.

What is this law, and how will it be used? Let us fill you in.

What Is the Congressional Review Act?

This law is intended to be an oversight tool for members of Congress, offering a check on federal agencies.