KOLKATA: A booth-level officer (BLO) engaged in the ongoing Special Intensive Revision (SIR) of electoral rolls died of cardiac arrest in West Bengal's Murshidabad district, with his family alleging that mounting work pressure pushed him to the brink.

This is the fourth such death reported in the state since the exercise began on November 4, sparking a political blame game.

Officials identified the deceased as Zakir Hossain, a teacher at a state-run primary school who had been deployed as a BLO. He collapsed on Thursday afternoon after complaining of severe chest pain and was rushed to a nearby hospital, where he died later that night, family members said.

Relatives claimed Hossain had been under "tremendous pressure" juggling SIR duties and regular teaching work.

The strain increased, they alleged, because the primary school authorities refused to relieve him despite repeated requests, forcing him to manage both responsibilities simultaneously.

With Hossain's death, the number of BLO fatalities linked to alleged SIR-related stress has climbed to four.

Earlier, a BLO in Purba Bardhaman district died of a heart attack, while two others -- one in Nadia's Chapra and another in Jalpaiguri's Malbazar -- allegedly took their own lives, reportedly unable to cope with the workload.

The deaths have fuelled sharp political exchanges.

Trinamool Congress leaders, including Chief Minister Mamata Banerjee, have accused the Election Commission (EC) of burdening BLOs with an "inhumane" and "unplanned" workload.

Addressing a rally in Bongaon earlier this week, Banerjee claimed that at least 10 BLOs deployed for SIR had been hospitalised and three had already died.

"In Murshidabad, one more BLO has died due to the pressure put by the EC in connection with SIR.

The total number of deaths is four, and nearly 14 others are undergoing medical treatment," a senior TMC leader said on Friday.

The BJP, however, rejected the allegation, contending that the stress felt by BLOs stemmed not from the Election Commission's directives but from political and administrative pressure exerted by the ruling party in the state.