An environmental group on Monday harshly criticized the way New York reviews wastewater pollution permits, saying the process has likely increased pollution in the state’s waterways and has violated federal laws.

The group, Environmental Advocates of New York, said in a report that the process is so flawed that it allows discharges from thousands of factories and sewage treatment plants to go without a thorough review for a decade or longer.

“We have no idea what this is doing to our waterways, and neither does the state,” said Katherine Nadeau, water and natural resources program associate for the group and author of the report. “When you’re going 10 to 20 years without a thorough review, it means you have no idea if the permit that a plant is operating under is protective of the waterway at all.”

Most reviews for major pollution permits are cursory, requiring little more than a self-evaluation by a plant operator, the report said. These permits account for more than 99 percent of the pollution that is discharged in New York waterways.