The students, who wanted to test its strength, were using the Carolina Reaper pepper to make a super-spicy chilli con carne.
But when their neighbours started coughing and falling ill, they dialled 999.
Theresa Morgan, 19, and her housemates were next door when they all started feeling unwell.
She told The Sun: "There was no smell or smoke so we thought it was carbon monoxide. The girls looked outside to see their other neighbours all running out of their houses while coughing.
"The fire crew arrived and wore gas masks while using an industrial ventilator fan to de-spice four properties on the road."
Theresa added: "They said it was the most stupid thing they had been sent out to in 20 years."
The Carolina Reaper is 450 times hotter than Tabasco sauce.
To say sorry, the chilli-loving boys bought the girls a case of beer. What great neighbours!
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