Two of the nation’s largest summer camp organizations — the YMCA of the USA and the American Camp Association — released a “field guide” on Monday on how to operate safely this summer amid coronavirus concerns. About 14 million people typically attend 8,400 overnight and 5,600 summer day camps, according to the guide.

The 80-page document gives detailed advice for social distancing, transportation, and campers and staff with preexisting medical conditions. The guide also gives specific information about activities such as crafts, swimming and performing arts. The information is meant to supplement the one-page flowchart released by the CDC last week.

According to the guide, camps shouldn’t open if state and local officials don’t allow it. They should also be in areas that met the third phase of White House guidelines, which call for a two-week decline in COVID-19 cases and hospital capacity to care for new patients.

First, camps should pre-screen all staff and campers for COVID-19 symptoms, according to the guide. During camp, directors and administrators may choose to take temperatures daily and isolate or send home people with symptoms.

The guide suggests that overnight camps operate as a “bubble,” allowing only staff and campers who have tested negative. They may also follow shelter-in-place guidelines for the duration of the camp.

In addition to the “bubble” concept, camps may incorporate “cohort” or “household” rules that keep staff and campers in small groups for daily activities, particularly ones that require close contact. This tactic could limit the spread of a potential outbreak and allow staff to trace contacts.

Other recommendations include frequent disinfection, handwashing procedures and enough equipment, such as life preservers, so campers don’t have to share during the program.

Some of the recommendations could make operating a camp more expensive, NPR reported.

“I am aware of some Y camps that have made basically a business decision that it’s better to forego this summer, cut expenses way back and be prepared for next year,” Paul McEntire, chief operations officer of the YMCA, told NPR.

Some summer camps are planning to reopen, even if delayed, the news outlet reported, including camps in Arizona, Colorado, Connecticut, Montana, New York and Texas. Other have canceled programs entirely.