Reuters reports: Days after a suspected poison gas attack killed hundreds of people in crop-growing suburbs, residents of the Syrian capital say they are afraid their food and water supplies may be contaminated.

Western countries believe President Bashar al-Assad’s forces carried out the worst chemical weapons attack since Iraqi leader Saddam Hussein gassed thousands of Kurds in 1988. Syria’s government denies any role in the deaths and blames rebels.

Whoever is to blame, grandmother Hana said her three daughters were now fretting about what to feed their children.

“They keep calling me throughout the day, and they are frantic. They ask: ‘Mum, what about the watermelon? Does it absorb the chemicals? What about the milk?’ I try to calm them down, but I’m very worried myself. What if it takes years for any effects to show up in the children?” she said.

The poison gas hit the Ghouta area, where acres upon acres of agricultural land supply the capital of 3 million people with fresh vegetables, meat and dairy.

“I hope God will protect us. Because I would really rather plant my own tomatoes and vegetables, but how will they grow in my third floor apartment? I don’t even have a balcony,” said Um Hassan, another grandmother.

She it was the first time she was seriously worried about food contamination since the U.S.-led invasion of neighboring Iraq made Syrians fear contamination of imported food.

The Syrian authorities have yet to respond with any clarity about whether people need to take special precautions to protect themselves from possible contamination.

It is not yet clear what poison or mixture of poisons were responsible for the killings.

Sarin, which the United States and France believe was used in previous, smaller incidents in Syria, mixes with water. People can be exposed to it by touching or drinking contaminated water, according to the website of the U.S. Centers for Disease Control and Prevention. People can also be exposed by eating contaminated food.

“Do we have to keep our windows closed? How long does the poison stay in the air? I hear different things from people,” said 40-year-old man who works as a physical therapist and lives less than a 15-minute drive from one attack.

“Do we have to worry now about leaving the city? Are we considered contagious?” he said.