Dust, fire-flakes and contaminated water from the massive fire at a Coupang warehouse in Icheon last week have been killing fish, damaging farms and causing health problems among local residents.

More than 1,800 dead fish were found in three reservoirs about 1 kilometer away from the Coupang warehouse in the three days to Monday, according to Icheon city officials.

A city official said a natural surface active agent used in the firefighting water could have killed the fish as it blocks the air.

The city sent the dead fish specimen to the National Forensic Service, and water samples from the reservoirs and connecting streams to a provincial environmental research center for detailed analysis.

Scores of residents in nearby villages have reported headaches and eye pain after the fire that burned down the e-commerce giant’s four-story building which has a floor space the size of 15 soccer fields.

Dust from the fire swept farms as far as seven kilometers away from the warehouse.

The fire that started in the second-floor basement Thursday morning was believed to be under control several hours later, but it spread quickly as flames spread across flammable packing material such as paper, plastic and stickers.

On Tuesday, Coupang began receiving reports from residents who suffered damage from the fire in order to compensate them based on its own investigation.

On Monday, a worker at the Coupang logistics center claimed that a company official repeatedly dismissed his report of fire as well as a fire alarm early Thursday.

The worker wrote in an online petition on the website of the presidential office that the fire alarm initially went off between 5:10 and 5:15 a.m. on Thursday, but no one took action as false alarms were common.

As he walked toward the first floor entrance about 10 minutes later, however, he saw the lower part of a staircase full of smoke, and reported it, only for this to be disregarded as a joke, he claimed.

The fire at the Deokpyeong logistics center was reported to the fire authorities at 5:36 a.m.

The worker wrote that he should have retrieved his phone, which he was not allowed to carry while on duty, and called 119 instead of wasting his time trying to talk to company officials.

Coupang said the company was still looking into whether the worker’s claims were true or not, and was actively cooperating with the police and fire authorities’ investigation.

Authorities said earlier that they suspect that a spark from a power outlet caused the fire, citing security camera footage.

By Kim So-hyun (sophie@heraldcorp.com)