New York, Jan 31 (IANS): Non smokers beware! Frequently visiting smoking areas in houses, apartments, offices and hotels is just as deadly as first-hand or second-hand smoke, shows research.

Third-hand smoke is a potential health threat to children, spouses of smokers and workers in environments where smoking is allowed, it warned.

“We studied on mice the effects of third-hand smoke on several organ systems under conditions that simulated third-hand smoke exposure of humans,” said Manuela Martins-Green, a professor of cell biology at the University of California, Riverside.

“We found significant damage occurs in the liver and lung. Wounds in these mice took longer to heal. Further, these mice displayed hyperactivity,” Martins-Green added.

Contamination at smokers' homes is high - both on surfaces and in dust - including children's bedrooms.

Re-emission of nicotine from contaminated indoor surfaces in these households can lead to nicotine exposure levels similar to that of smoking.

The research team was surprised to find that the damage caused by third-hand smoke extends to several organs in the body.

The researchers found that the mice exposed to third-hand smoke in the lab showed alterations in multiple organ systems and excreted levels of a tobacco-specific carcinogen similar to those found in children exposed to second-hand smoke and consequently to third-hand smoke.

“There is a critical need for animal experiments to evaluate biological effects of exposure to third-hand smoke that will inform subsequent human epidemiological and clinical trials,” said Martins-Green.

“Such studies can determine potential human health risks, design of clinical trials and potentially can contribute to policies that lead to reduction in both exposure and disease,” she added in the study that appeared in PLOS ONE.