SOUTH BEND, Ind. &#8212 The images of oil and debris burning in Cleveland’s Cuyahoga River in 1969 still stand as an iconic symbol of modern-day industrial pollution.

Subsequent demands for environmental protection led to passage in 1972 of the federal Clean Water Act and pledges to eliminate discharges of pollutants by 1985.

Nearly 35 years after the legislation passed, however, a dispute over a northern Indiana oil refinery illustrates that questions remain over how best to protect some of the country’s most valuable resources.

The Clean Water Act requires states to update water quality standards every three years and to update wastewater permits every five years.

The Environmental Protection Agency says no more than 10 percent of permits should be past their expiration date.

But 30 states fall short of the EPA goal, and in some, more than half the wastewater permits are outdated. Alaska has 75 percent of all permits out of date.

Sixty percent or more of the permits in New Hampshire and Montana are outdated.

EPA officials blame some of the backlog on a lack of money and resources, especially in five states – Alaska, New Hampshire, Massachusetts, New Mexico and Idaho – where the EPA, not the state, grants wastewater permits.

“I’m not in a position to send 10 more permit writers up to Boston to write permits for Massachusetts,” said Jim Hanlon, director of the EPA’s office of wastewater management. “We do what we can with the available resources.”

But even states that grant permits face backlogs.

In Montana, for example, 60 percent of the permits are outdated.

Bonnie Lovelace, chief of the water protection bureau of Montana’s Department of Environmental Quality, said a shortage of permit writers, changing standards and staff retirements have contributed to the state’s backlog.

She said the department prioritizes new permits over renewing old ones.

“It’s the unpermitted people we want to get under permit,” she said.

Environmentalists say expired permits make it impossible for states and the industry to keep up with evolving standards, putting the nation’s waters at risk.

“Newer and better and more stringent requirements can’t be imposed if you don’t issue another permit,” said David Ullrich, executive director of the Great Lakes and St. Lawrence Cities Initiative, who worked for EPA for 30 years.

Indiana meets the EPA guidelines; just 9.9 percent of its permits have expired.

The state began pushing to update permits in 2005, when 276 facilities had old permits, said Amy Hartsock, spokeswoman for the Indiana Department of Environmental Management.

The original permit at the BP refinery in Whiting, about 15 miles southeast of Chicago, was first issued in 1990 and had been renewed administratively every five years since.

This summer, the state granted a permit allowing BP to dump 54 percent more ammonia and 35 percent more suspended solids into Lake Michigan as part of a refinery expansion project.

State officials said the limits were more stringent than federal rules and would not harm the lake.