Over a thousand people working in 26 limestone grinding factories in Burimari land port area of Patgram upazila under the district are under serious health hazard.
Regular exposure to silica dust, an element of limestone, can lead to silicosis, an incurable lung disease, within months.
At least 21 people died from silicosis in the last five years, and a number of day labourers are suffering from the disease, said Dr Jahangir Alam Sarker, civil surgeon of Lalmonirhat.
"The disease develops as 'simple silicosis' at the primary stage and if the patient refrains from further exposure, the disease does not get worse. But if the disease gets into the next stage, the patient's condition worsens gradually," he said.
Many of the patients cannot afford the treatment cost, Azizul Islam, a limestone grinding worker at Burimari.
"We know silica dust is the main cause of silicosis and we inhale it while working in the factories. But we are helpless due to lack of alternative employment opportunity in the area. Agricultural work here is seasonal and there is not enough work for everyone," said Jasim Uddin, another worker.
"White dust produced during the crushing of limestone thickens the air in and around the factories. Layer of dust makes us look ghostly," said day labourer Nur Islam, 36, who has been working at a factory for the last six years.
Several labourers said they feel breathing problem while working.
Safar Uddin Miah, president of Burimari Land Port Sangjukta Sramik Federation, said, "The labourers are doing the hazardous job in absence of sufficient employment opportunity in this region affected by yearly monga (seasonal famine-like situation). We urged the factory owners to ensure safety measures, especially face masks, for the workers but to no effect."
Labourers, mostly young men, work from dawn to dusk for daily wage of Tk 300 to Tk 350 to make lime powder to be used as poultry feed.