(Third of a series)
For several years now, the Department of Health (DOH) has been hearing stories of taxi drivers supposedly falling ill due to extended exposure to liquefied petroleum gas (LPG) fumes.
But up to now, these stories are considered “theories” in the absence of scientific evidence that would directly link inhalation of LPG fumes to a range of health problems particularly among taxi drivers, according to health undersecretary Teodoro Herbosa.
“We really need detailed studies before we can make a conclusion,” Herbosa said in a phone interview. “As of now, these are just theories by taxi drivers and until there is hard evidence, DOH cannot act on a policy.”
Without proper study, Herbosa said, it would be reckless to pin down LPG fumes as the main culprit behind the respiratory illnesses afflicting these drivers who are exposed to a variety of other unhealthy conditions.
Drivers work 24/7 to earn their “boundaries,” negotiating Metro Manila’s congested and polluted streets for longer periods of time and smoking on their quick breaks, Herbosa said.
Rigorous tests needed
He acknowledged that chemicals in the LPG can be absorbed into the blood through inhalation.
But to determine what levels are safe and what are toxic can only be established through rigorous tests, including blood and air quality monitoring, which a taxi driver using LPG fuel must be willing to undergo.
Reports of taxi drivers suffering from respiratory and skin ailments due to driving LPG-fueled cabs have reached DoH since 2007 under then Health Secretary Francisco Duque III.
In July 2007, Duque ordered the department’s Environmental and Occupational Health Office (EOHO) to study the possible hazards linked to LPG-fueled vehicles following complaints of breathing difficulty and skin allergies among taxi drivers.
He has also urged the Land Transportation and Franchising Regulatory Board and the Department of Science and Technology to join in undertaking the research.
Unfinished study
A check with the EOHO showed that it has yet to finish the study, which was launched about a year ago, according to Ana Rivera, supervising head project officer.
“We still need additional drivers to examine,” Rivera told the Inquirer. The study has observed roughly 20 drivers, she said.
The study being conducted is in collaboration with the UP-PGH National Poison Management and Control Center, an institution that manages poison cases and studies the health effects of chemical exposure among high-risk communities.
The Inquirer’s entertainment reporter Pocholo Concepcion has talked to more drivers than has the EOHO about the problem in his daily commute. Pocholo’s concern about the fumes assaulting his nose whenever he rides an LPG-powered cab led to this series of articles.
“We are having difficulty recruiting volunteers to participate,” said Dr. Lynn Panganiban, the center’s chief. She said it was still premature to say whether a taxi drivers’ exposure to LPG fumes posed health risks.
Until the study is completed, health experts can only advise cab drivers to make sure that their vehicles’ gas pipe connections are properly installed so that the LPG fumes don’t go through the air-conditioning system.
“I assume that if the piping system of the LPG to the fuel line is correct, there won’t be any problem,” said Herbosa.
Gas evaporates swiftly
Dr. Marilyn Alentajan, president of the Philippine College of Occupational Medicine (PCOM), said no study has proven yet that there is immediate health hazard in using LPG-fueled vehicles.
“I don’t see any because it (LPG) easily evaporates at room temperature and has less carbon emission unlike the regular gasoline,” Alentajan said in a phone interview.
An affiliate of the Philippine Medical Association, PCOM is an organization of occupational medicine practitioners working for the health, wellness and safety of workers in all occupations while preserving the environment.
Alentajan said the hydrocarbons from the LPG evaporate under normal conditions but noted that the fumes in an enclosed environment may have an effect on the respiratory tract.
Bronchial spasm
Long exposure to LPG fumes may trigger bronchial spasm, a sudden constriction of the muscles in the walls of the bronchioles, causing difficulty in breathing, she said.
“But it’s just temporary,” Alentajan said. Because the airways get irritated, dryness and thirst are also among the symptoms of bronchospasm, she added.
She highly recommended that the engineering component on the use of LPG as an alternative motor fuel be improved. “Per se, it is less hazardous than petroleum,” she said.
Other factors
By the nature of their work, taxi drivers, and even commuters, are exposed to air pollution and smoking every day, said Dr. Norberto Francisco at the Lung Center of the Philippines (LCP).
“How can you put the blame on LPG when there are many other factors, like pollution or smoking?” Francisco, a pulmonologist, said in an interview. “It’s impossible to determine that because of what we call the confounding variables.”
That’s why, complaints by drivers and commuters of dizziness, headache, dryness of throat, thirst and breathing difficulty, among others, as caused by exposure to LPG are “merely anecdotal” and have no “scientific basis,” he said.
“When you analyze data on your research, you talk of hundreds or thousands of subjects,” Francisco said. ‘’Unfortunately, if you look at research protocols, we can’t provide data especially because LPG is new in the market. But even it if has been in use for a long time, it’s difficult to determine it because of smoking and pollution.”
As of now, the Lung Center has no data on drivers who had themselves checked or were confined mainly because of exposure to LPG, according to Francisco, the hospital spokesperson.
“What we get are infection, bronchitis, inflamed airways. Those things are the end-result of so many risk factors. We just treat the end-condition because we have to make them feel better,” he said.
Design new research
Neither does the Lung Center have any research on the effects of fuel on the health of public utility vehicle drivers, precisely because of the factors of pollution and smoking, the doctor said.
One sure-fire way to find out the possible correlation between these ailments and exposure to LPG is through research in a controlled environment, according to Francisco.
This can be done by grouping taxi drivers into two—LPG users and non-LPG users and making sure all the subjects are nonsmokers and are not exposed to pollution.
Ideally, this should be done in pollution-free countries, like Denmark, Sweden and New Zealand, Francisco said.
“The only way you can do this is do a future research. You can’t base it on past history. Design a new research and follow them up in time,” he said. “That’s the only way you can find out. Otherwise, we will not have a valid conclusion.”
(Tomorrow: The other side—the believers in LPG)