PORT-AU-PRINCE, Haiti – When Guerrier Lejean feels nature’s call, he relieves himself in the bushes of his urban encampment.

He has been doing so since the Jan. 12 earthquake left him homeless, and so have most of his approximately 2,500 neighbors who huddle in shelters made of sticks and bedsheets.

The crowded camp near the Port-au-Prince airport has no bathrooms.

The dire shortage of toilets in the more than 300 encampments that have sprouted across Port-au-Prince is more than a matter of inconvenience.

With rainy season expected to begin next month, sanitation and hygiene loom as urgent health concerns for about 1 million people living in fields and vacant lots in quake-struck areas in and around the capital.

Former President Clinton, the U.N.’s special envoy to Haiti, called sanitation the most pressing need facing quake victims.

“They have no place to go to the bathroom, and as a result they may be contaminating every piece of standing water,” Clinton told Fox News’ Major Garrett. And that, he said, could lead to diarrhea, dysentery, cholera and tetanus.

Aid workers say coming rains will increase the risk of disease outbreaks. Authorities are racing to get latrines built and portable toilets and hand-washing stations installed.

“Once the rain comes, the feces will flow everywhere,” said Therese Dooley, senior adviser for sanitation and hygiene at UNICEF. “A gram of feces contains billions of bacteria and pathogens. What you have to worry about is them getting into the food chain and the mouth.”

Haitian officials hope to have in place at least 18,000 latrines, one for about every 50 displaced people, within a few weeks.

Aid groups are digging pits, installing portable toilets and erecting latrines with above-ground storage tanks. Camps are gradually being outfitted with hand-washing stations: 2-liter plastic sacks or 200-liter drums with nozzles and soap.

UNICEF has handed out hygiene kits with buckets, soap, toothbrushes and sanitary napkins to 86,000 families.

No outbreaks of disease have been reported, but the task has not been easy.