Painters working in one of the buildings at the old Arizona Chemical plant site Thursday afternoon accidentally knocked a large industrial thermometer from a wall, causing it to break and spill some mercury, said City Manager Ed Pinero by telephone last night.

Pinero said the Mississippi Department of Environmental Quality had been informed and that an environmental clean-up company —U.S. Environmental — had been called in to clean up the mercury and safely dispose of it.

Mercury is classified by the U.S. Environmental Protection Agency as a hazardous substance due to its poisonous properties. The EPA has issued warnings in recent years that some fish should be eaten only in small quantities, and sometimes not at all by pregnant women, because some fish contain mercury derived from the food they eat. The natural element is a silver-gray metal and the only metal that is liquid at normal temperatures. It is used in a variety of scientific instruments, including thermometers and barometers.

Mercury poisoning can cause neurological damage, said Earl Etheridge, state on-scene coordinator with Mississippi Department of Environmental Quality.

Etheridge said the workers found a two-foot long thermometer that contained about two pounds of mercury. Picayune Fire Chief Keith Brown said when the painters picked up the device, part of it fell trough a hole in the device to the floor. Etheridge said about seven to eight ounces of mercury were spilled in the process.

MDEQ contracted with US Environmental Services to enter and clean the site. Its workers wore special suits to keep them from being exposed to the chemical. Brown said the cleanup began Thursday at about 4:30 p.m. and went on until about 2:30 a.m. Crews suited up again this morning to finish the job.

“Hopefully we’ll finish today,” Etheridge said.

The clean-up crew is using a combination of heat and ventilation to rid the site of the mercury. The clothes and boots from the painters and some city employees had to be confiscated and tested for mercury contamination. None of the items were returned because they all tested positive for mercury, Brown said.

Brown said mercury can cause contamination through contact, but most contamination is caused by inhalation if it is heated.

To keep the clean-up crew from breathing the substance, they wore face masks while they conducted the clean up. The clean-up crew is using a process of cleaning, heating and checking for mercury levels to ensure the site is safe to occupy again.

The main office building at the old chemical company site that is now the new Picayune City Hall was not involved in the spill and did not have to be evacuated.

Administrative assistant Diane Frierson said Friday morning that the clean-up company had gone through all the buildings at the old Arizona Chemical site last night and checked them all for mercury.

The City of Picayune bought the Arizona Chemical Co. site from its parent company, International Paper Co., last year. The old office building is the new City Hall and several other buildings on the site are being prepared to use for storage and other uses the city may have for them. The old City Hall is now being used by the Picayune Police Department for some of its office needs.