What do we know about health effects of styrene gas exposure?
On early Thursay morning, a gas leakage in Andhra Pradesh's Visakhapatnam has led to death of at least 11 people, including an eight-year old child. Hundreds of people have been hospitalised. A gas called styrene is thought to be the reason behind the deaths.
A gas leak from a private plastic making plant in Andhra Pradesh's Visakhapatnam early Thursday morning has led to nearly a dozen deaths. A chemical named styrene is thought to be behind the tragedy.
Styrene is the 20th most-used chemical in the world, according to the World Health Organization, and is also known as PVC gas (polyvinyl chloride). It is usually used in the production of polystyrene plastics and resins.
The Agency for Toxic Substances and Disease Registry (ATSDR) of the Centers for Disease Control and Prevention of the United States says that "Chronic exposure to styrene in humans results in effects on the central nervous system (CNS)", with symptoms such as headache, fatigue, weakness, depression, CNS dysfunction (reaction time, memory, visuomotor speed and accuracy, intellectual function).
But for such exposure, the gas should present more than a thousand times higher than the levels normally found in the environment. This implies that the leakage at Visakhapatnam was a major one.
One clinical study has shown that the inhalation of at 376 ppm for 25 minutes had resulted in nausea, a sense of inebriation and headache. But there haven't been studies on the health effects due to exposure at further higher concentrations.
Low chances of long-term effects
The chances of long-term health effects because of exposure to styrene vapour, which leaked from a chemical plant, are less and illnesses caused by the gas are not universally fatal, AIIMS Director Dr Randeep Guleria told PTI.
As far as treatment is concerned, there is no specific antidote or a definite medicine for reversing the effects of this compound. The therapy remains mainly supportive, he said.
The Visakhapatnam leakage has led to 11 deaths so far. Several people are in hospitals and most of them are in a stable condition.
To a question on whether the impact of the exposure can be long-term as was in Bhopal gas tragedy, Dr Guleria said, "The gas doesn't stay for a very long time. The chances of long-term impact are less as the compound metabolises and leaves the body quickly."
"This is an acute exposure rather than a chronic exposure. But we will have to follow up and see. As of now, the data doesn't suggest any significant long-term effect."
Those who have had a very close exposure, are the ones with a higher chance of experiencing severe effects, he said, adding a house-to-house visit in the surrounding areas have been initiated to see if anybody has developed medical problems.
Guleria said inhalation and ingestion of styrene can affect the skin and the eyes.
Absorption of this compound can affect the central nervous system causing headache, nausea, vomiting and fatigue. People become unsteady, have difficulty in walking and sometimes also can fall over. High exposure can lead to coma, pulmonary oedema and irregular heartbeat, he said, adding the syndrome is known as styrene sickness.
Effect on the skin is usually mild in form of irritation, itching and some degree of dermatitis. It causes irritation in the airways and depending on the degree of the exposure the effect can be much higher, the AIIMS director said.
He said the first thing that has to be done is to remove individuals from the affected area, as has been done aggressively.
Eyes need to be washed with water. Tissues or towel can be used to clean the deposition in the skin, Dr Guleria said, "Individuals have to be monitored for any breathing difficulty or drowsiness because the compound can affect the lungs and the brain."
"The main treatment strategy is to watch out for any breathing difficulty and airway management. Some of these patients will be required to be incubated and put on a ventilator. Many will just require oxygen therapy and can be monitored in terms of their oxygen requirement, respiratory rate and their CNS depression," he said.
At a press briefing, Director General of National Disaster Response Force (NDRF) S N Pradhan said leakage from the factory is now minimal but the force's personnel will be at the spot till it is plugged.
Pradhan said 500 people belonging to 200-250 families living in 3-km radius have been moved to safer places.
Member of the National Disaster Management Authority Kamal Kishore said about 1,000 people living in nearby areas of the factory have been exposed to the gas leak.
(With PTI inputs)