New Jersey, New York COVID-19 quarantine expands to more than half the U.S.

Travelers from more than half the U.S. are now being asked to quarantine if they come to New Jersey, New York or Connecticut as coronavirus continues to spread outside most of the Northeast, Gov. Phil Murphy announced Tuesday.

The list of states now stands at 31 where COVID-19 test rates are higher than 10 positive cases per 100,000 residents or a state with a positivity rate higher than 10% over a seven-day rolling average.

Ten states were added Tuesday including nearby Maryland and Virginia. Delaware returned to the list, which drew a strong rebuke from Gov.  John Carney who said he was "mad as hell."

Murphy said a few recent outbreaks in New Jersey can be attributed to people returning from states that are now considered hot spots.

The policy essentially works on the honor system and there is little, if any, teeth in terms of enforcement.

"I strongly encourage all individuals arriving from these hotspot states to proactively get a COVID-19 test and self-quarantine,” Murphy said in a statement Tuesday.

Delaware Gov. John Carney said Tuesday adding his state to the travel advisories "doesn't make any sense."

Delaware health officials said Tuesday that the state has a COVID-19 positive rate of 4.2% and 105.3 cases per day, on a five-day average. Carney believes Delaware was re-added to the list because it had two recent days where there were more than 100 daily cases confirmed.

"That makes no sense," Carney said. "We're better today than when we were first put on the list two weeks ago. And we're better today than we were last week, when we were taken off the list."

The list of states has more than tripled in less than three weeks as coronavirus continues to spread at a rapid rate outside of the tri-state area.

Upon entering New Jersey, travelers are advised to voluntarily stay indoors for 14 days and go out only for medical care or to buy food and other essential items. Those who get tested in New Jersey can end their quarantine early if the results are negative.

But the quarantine advisory also allow for people "passing through designated states for a limited duration through the course of travel," which may exempt visitors from nearby states like Delaware or Maryland.

Business travelers are exempted as well as those who have less than a 24-hour layrover.

NJ quarantine list includes 31 states: Alaska, Alabama, Arkansas, Arizona, California, Delaware, Florida, Georgia, Iowa, Idaho, Indiana, Kansas, Louisiana, Maryland, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Mexico, Nevada, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Utah, Virginia, Washington and Wisconsin .

Minnesota was taken off the list Tuesday.

Meredith Newman of the Delaware News Journal contributed to this article.

Scott Fallon covers the environment for NorthJersey.com.