WHO warning of brain cancer risk for mobile phone users had left many people alarmed over the issue but resigned to needing the devices to do their jobs.
"It's really scaring me. Usually, I put it on a speaker, or I only use it in an emergency. And it is really scary because of my kids," Milite Andom, 49, a street vendor with teenaged children, told AFP.
"They talk too much on their cells (mobiles), and I was telling my kids, but they do not want to hear it," Andom added.
The WHO's International Agency for Research on Cancer (IARC) announced Tuesday after meeting in France that radio-frequency electromagnetic fields generated by such devices are "possibly carcinogenic to humans."
The IARC cautioned that current scientific evidence showed only a possible link, not a proven one, between wireless devices and cancers.
But the news was jarring to people whose lives have changed dramatically in recent years with the personal convenience of the cellphone, to the point where many spend hours with the devices pressed to their heads, day in and day out.
When setting up homes, many people forgo traditional land lines, cells pressed to the ear.
There are now about five billion mobile phones registered in the world, their use so ubiquitous that they have begun to eclipse traditional landlines. Worldwide mobile sales increased 32 percent last year, tracking firms say.
But health experts said it was still unclear what might happen with greater exposure over longer periods.
"Everything new, they just throw it out there with no real testing. And 10 years later they tell you it is all bad for you," sighed bike messenger David Daudu, 31, who spends more than 12 hours a day on the street and on the phone.
Asked if the warning might change his habits, Daudu was clear: "I have no option, workwise."
His sentiments were echoed by construction foreman Michael Harris, 41.
"What are you going to do?," asked Harris, who spends hours every day receiving and relaying instructions, cell at his ear.
"You want to try to stay healthy, but this is the way business is being done today.
Some mobile users reluctant to change their phone habits said they hoped someone would hurry up and disprove the WHO findings.
"Two weeks from now, they'll probably come out with (a study) rebutting it," quipped bank teller Nick Bolden, 25.
The US Centers for Disease Control maintains that research so far does not lean toward a significant association between cell phone use and health effects.
Bernadette Burden, a spokeswoman for the Atlanta-based agency, said of the new report: "We take research seriously. And our experts here are going to examine it very carefully."
Burden noted the phone-use potential risk level announced by the WHO was in the same class as that of coffee.
Yet she told AFP: "We recognize that it is a very serious issue."