Heritage-Crystal Clean, owner of North America’s second-largest rerefinery, announced the expiration of a waiting period called for under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, for the company’s agreement to be bought by private equity firm J.F. Lehman & Co. for $1.2 billion. The expiration on Sept. 1 was a condition to the closing of the transaction, which is expected to occur in the fourth quarter, subject to conditions.