From its start at the Easton Reservoir, the Mill River meanders 16.3 miles to Southport Harbor, where it empties into Long Island Sound.

The Mill River's northern reaches are unique in Connecticut, Trout Unlimited says, because it's the state's only stream where three types of trout -- brown, rainbow and brook -- all spawn.

In Fairfield, the stream alternately widens and narrows through some of our prettiest areas -- Lake Mohegan, Samp Mortar Reservoir, along Brookside Drive, past Flower House Drive to Perry's Millpond.

It widens along Bronson Road until I-95 passes overhead.

And it's about there, just north of the Post Road, that scenic charm turns to industrial harm.

The Mill River there became an industrial drain, sucking in heavy metals from factories built near its banks.

It's been 30 years since Exide Group Inc. closed its battery-manufacturing plant and nearly as long since it dug the first shovelfuls of lead-polluted silt from the river. But full cleanup of the river has not begun.

Those lead particles have been joined in the river by chromium particles from Superior Plating Co., which continues to operate nearby.

Infants born when the Exide cleanup plans were first being drawn have graduated from college. They've gone on to law school and medical school. They carry briefcases to court now, wear stethoscopes around their necks at hospitals.

We've waited forever, it seems, for the Mill River to be cleaned up. And we're going to have to wait longer.

But the possibility now that there could be two separate cleanups -- one to remove Exide's lead particles, followed by a second one to remove Superior Plating's chromium particles -- is simply absurd.

Plans to remove the lead are farther along than those to remove the chromium. Fairfield Conservation Director Thomas Steinke would like to slow the first one down, speed the second one up and get them done at the same time.

That makes perfect sense and would put the long-delayed cleanup on a firm schedule. Unfortunately, it's not Steinke's call.

Exide and Superior Plating are under separate cleanup orders from the state Department of Energy and Environmental Protection -- now called the DEEP since energy has been added to the former DEP's oversight.

And although the DEEP agrees doing both jobs simultaneously would be preferable, it can't guarantee it will happen. Its engineers say some of the chromium is in the same locations as the lead, and as lead-polluted silt is dredged from the river, the chromium would come up with it.

But getting at other chromium deposits will require other measures.

We urge both town and DEEP officials to press Exide and Superior Plating to cooperate in completing one painstaking and thorough cleanup of the river.

If a coordinated effort to remove the lead and chromium would take a couple of years longer than Exide's plan to remove only lead, then we should be patient. Do it once and do it right.

Any cleanup -- whether joint or separate -- will not remove all the metal particles from the river; that would be impossibly expensive. The plan only is to reduce their presence to "acceptable levels" -- a prescribed number of milligrams per kilogram of silt.

The toxins in the river are invisible to passersby.

The Exide property's appearance is a far cry from the early 1980s. Gone are the hulking shells of brick buildings; gone are countless truckloads of contaminated soil. In its place is a flat expanse of grass that looks like a middle-school soccer field; all it needs is a pair of goals.

The town would be wise to begin thinking in earnest now about what the best use of the property would be. Fronting on Post Road, I-95 exits two minutes in either direction and a short walk to downtown, the remediated parcel would have developers -- and the tax collector -- salivating.

A prime location for a shopping center, medical complex or river-view condominiums awaits. Ah, yes, the river view. Could it be a fishing spot instead?

Trout Unlimited says wild trout are among the ultimate indicators of how healthy an ecosystem is. They need clean, cold, highly oxygenated water to survive. Would they mind a little leftover lead and chromium?