When shopping for appliances, eco-conscious consumers trust the EnergyStar label to help them find the ones that are truly energy-efficient. But it seems that trust may be misplaced, after an internal audit found that the Energy Department doesn’t properly track whether manufacturers have met the required specifications for efficiency.

The report found that companies that make refrigerators, washing machines, dishwashers, water heaters and room air-conditioners aren’t required to have independent laboratories evaluate their products.

The government also hasn’t followed up on a 2007 promise to conduct “retail assessments” to ensure that products marked with EnergyStar labels deserve them.

The voluntary labeling program was created in 1992 by the U.S. Environmental Protection Agency to help reduce greenhouse gas emissions by identifying the most energy-efficient appliances for consumers.

The EPA has since partnered with the Energy Department to create more than 60 categories of products that are supposed to use less energy while maintaining performance levels at or above those of comparable products.

These findings are just the latest in a series of reported flaws in the EnergyStar program. In September, Consumer Reports raised questions about the reliability of the label.

Mark Connelly, deputy technical director for Consumer Reports, said that the program’s test procedures are outdated. Other critics charge that the energy efficiency standards set by EnergyStar are too low. Last December, the EPA’s inspector general said weak oversight by the agency meant the efficiency of some products might be inaccurate, leading to the audit.