WASHINGTON — Most people who smoke want to quit, and the 2010 health care law is supposed to make it easier for them by requiring many insurance plans to cover smoking-cessation treatments with no out-of-pocket cost to members. But a recent study found that details about what is covered and who pays for it remain confusing and inconsistent.

‘‘We were taken aback at the extent to which the policies were rife with confusing language, conflicting coverage, and gaps in coverage,’’ said Matthew Myers, president of the Campaign for Tobacco-Free Kids, an advocacy group that commissioned the study.