If you are on the Essential Plan and your household income sits somewhere between roughly $31,000 and $40,000 for one person, there is a good chance your coverage ended on July 1 and you have not fully dealt with it yet.

That is not a criticism. It is the predictable result of a change that happened quietly, in the middle of the summer, to a program that worked so smoothly most people forgot they were enrolled in it.

The deadline that matters now is August 30.

What changed

New York's Essential Plan has covered lower-income residents who earn too much for Medicaid but not enough to comfortably buy private insurance. It has no monthly premium and no deductible, which is why it has been so popular and so invisible: you enroll, you get a card, and you stop thinking about it.

The program was funded through a federal 1332 State Innovation Waiver. Federal changes cut that funding, and New York's Department of Health moved to end the waiver and return to a narrower Basic Health Program structure. The practical effect was a lower income ceiling.

Before July 1, the Essential Plan reached households earning up to 250 percent of the federal poverty level. As of July 1, the top of the range dropped to 200 percent. Everyone who was in that 200 to 250 percent band lost eligibility on the same day.

In dollars, that band is roughly $31,000 to $39,000 a year for a single person and roughly $64,000 to $80,000 for a family of four.

The Long Island numbers

State Health Department figures from early May counted 34,477 Suffolk County residents and 28,940 Nassau County residents enrolled in that affected income tier.

The Fiscal Policy Institute, analyzing the change by region, put Long Island's total loss at nearly 70,000 people, including about 38,000 in Suffolk alone. That works out to roughly 2.4 percent of the Island's population, the same share as the statewide figure. Across New York, the institute estimates about 470,000 people are affected and describes it as likely the largest and most rapid loss of insurance in the state's history.

For scale, 70,000 people is more than the population of Long Beach and Glen Cove combined.

The August 30 date, and why it is not the usual deadline

Normally, losing coverage opens a 60-day special enrollment window and that is that. This situation got an extension.

New Yorkers who lost Essential Plan coverage on July 1 can enroll in a Qualified Health Plan through NY State of Health through August 30, and the coverage can be made retroactive to July 1. That retroactive piece is the part worth understanding. If you enroll before the deadline, the gap in July and August closes behind you, which matters enormously if something has already happened in those weeks.

Miss August 30 and you are looking at waiting for open enrollment, unless you have a separate qualifying life event.

What a replacement actually costs

This is where people freeze, and it is worth being precise, because the sticker price and the real price are not the same number.

A Qualified Health Plan is private insurance. Unlike the Essential Plan, it has a monthly premium and a deductible. But people in the affected income band qualify for federal premium tax credits that are applied immediately, every month, rather than at tax time.

One published illustration: an individual earning $35,910 a year, which is about 225 percent of the federal poverty level, was calculated as eligible for a tax credit of roughly $637 a month, bringing a benchmark Silver plan down to about $230 a month. Your own number depends on your income, your age, your county and the plan you pick.

The honest summary is that this is a real added cost for households that previously paid nothing, and also that the number people fear is usually much higher than the number they end up paying. The only way to find out which is which is to run your own situation through the marketplace.

How to do it

There are three doors, and they lead to the same place.

Online

Log in to your existing account at nystateofhealth.ny.gov. Update your income and household information first, because the tax credit calculation depends on it, then compare plans. If your information is stale, your subsidy estimate will be wrong.

By phone

The NY State of Health Customer Service Center is at 1-855-355-5777, open Monday through Friday from 8 a.m. to 8 p.m. and Saturday from 9 a.m. to 1 p.m., with support in more than 170 languages.

In person

Certified enrollment assistors will sit down with you and walk through it, and they are free. The same phone number will connect you with one in your community, and the NY State of Health site has a search tool for finding assistors by county. On Long Island, community health organizations and hospital financial counseling offices frequently have certified assistors on staff.

A few things worth checking before you pick

Check that your doctors are in the network of the plan you choose. The Essential Plan and the Qualified Health Plans are sold by many of the same insurers, but the networks are not automatically identical.

Check your prescriptions against the plan's formulary. This is the single most common unpleasant surprise in a plan switch.

Check whether anyone in your household is still eligible. The change hit a specific income band, so in some families a child may qualify for Child Health Plus while an adult moves to a Qualified Health Plan.

The Fiscal Policy Institute has estimated it would cost the state under $1 billion in the coming fiscal year to prevent the coverage loss for this population, and that argument is being had in Albany. That is a debate about next year. August 30 is this year.