Q. and A./ Louie Cheng on Chemical Contamination in Tianjin

Posted on September 24, 2015

By Didi Kirsten Tatlow September 18, 2015 4:59 am

Louie Cheng is the founding president of PureLiving China, a company based in Shanghai that specializes in improving indoor-air and water quality in one of the most polluted countries in the world. Mr. Cheng, a California native, served in the United States Army as a chemical warfare engineer before going into business, and he draws on that experience to assess and manage health risks where people spend most of their lives. His philosophy: “You control what you can: your home, your office, your church.”

After the Aug. 12 explosions in a chemical storage depot in Tianjin that killed at least 173 people and injured nearly 800, several companies affected by the disaster asked PureLiving to help them clean up. In an interview, Mr. Cheng discussed what he saw in Tianjin, why the explosions were not entirely a surprise and how people can protect themselves.

Q. What went through your mind when you heard that a chemical depot had blown up in Tianjin?

A. I saw the near real-time footage and was shocked, like everyone else, by the sheer size of the blast. But I’m a little cynical now. I don’t wonder anymore why these industrial accidents happen.

Q.Why is that?

A. I trace it to a combined culture of inadequate enforcement of rules and a lack of professionalism: “It’s cheaper to deal with the aftermath.” “Let’s play the odds rather than paying up front for safety.”

Q. Which chemicals in the depot should people be concerned about, and why?

A. Most of the chemicals I heard about initially, like ammonium nitrate and calcium carbide, were explosive in nature but not persistent, and did not have a high corrosive or biocide action, which we normally associate with chemical weapons.

The sodium cyanide was more of a concern, because it can generate hydrogen cyanide gas, which acts as a blood agent to cause incapacitation and death through locking up the blood’s ability to utilize oxygen. [About 700 tons of sodium cyanide were stored at the site.]

Q. What have been your main concerns about the blast since then?

A. It is one thing to speculate without having been on site, but having been in Tianjin to help with testing and decontamination for some clients, I would say I am less concerned, because the levels of sodium cyanide we encountered were very controllable, and we were able to recover equipment from areas impacted by the blast relatively quickly and without too much pain.

There was a tremendous kinetic blast, but in terms of persistent chemicals, cyanide is the weakest of them. It doesn’t spread from person to person like biological weapons, and it’s not persistent like radiation is. It’s not a heavy metal that accumulates in the body, like lead. In terms of chemical weapons, cyanide isn’t a very good one.

Q. Tell us about your background and what you learned about chemical contamination and dangers.

A. Nearly two decades ago, I was a nuclear, biological and chemical defense specialist for the U.S. Army. I was trained to test for the different types of nuclear, biological and chemical weapons, protect against them, decontaminate troops and equipment, and then train other troops in operating under these conditions. I have applied these skills to my work today as an indoor air quality consultant, and taught my staff to use the same principles of assessing, fixing and then monitoring.

Q. You run a company that offers clean air solutions in China. What should people who live in China know?

A. The main message we tell our clients, whether residential or commercial, is that it is “better to know.” Many people believe they’d rather not know what they’re breathing or drinking. To me, this is as silly as leaving China because of the fear of something unknown. If you know what’s in your living environment, you can then do something about it. Or if there’s nothing wrong, you can have peace of mind.

Q. Many people in China wear simple cloth or paper face masks when the air is very polluted. Are they of any use?

A. Mask effectiveness depends on two things: Is the mask material suitable for reducing the type of contaminant of concern in the air? For instance, in Tianjin, chemicals may have become valorised by heat, reaction with water or pressure, and formed poisonous gases. These gases would require an organic vapor canister respirator filter to remove, not the particulate N95 masks that many wear for day-to-day protection against PM2.5.

Assuming you are wearing the right type of mask, there has to be a tight seal, otherwise the pollutants can just follow the path of least resistance. This is usually a matter of finding the right size and fit for your face.

Q. Would you move to the Tianjin port area, or even Tianjin itself, now?

A. I would work in Tianjin because I have the tools for self-protection. But I would want to have a broad range of air quality testing and ongoing early- warning monitoring before I felt comfortable enough to send my family to live there.

Q. How do you assess the chemical contamination in different areas of the environment in China?

A. We work primarily in the indoor environment — home, school, office and factory — and mainly test the indoor air to first identify whether there are any known contaminants in high enough levels to cause health risks.

Then, if we find any odors or levels in the unhealthy range, we use hand- held electrochemical, optical or infrared sensing and experience of the built environment to “sniff” out sources. Once we have a sense of what the causes are, we can then advise on how to eliminate them.

In China, unlike in North America where I am from, pollution comes not only from indoors but also outdoors, causing a dilemma — how to remove the contaminants if the air outside is dirty too. We educate people in China to always think about balancing these two by filtering incoming air — instead of just shutting out the outdoors, while the indoor-generated chemical and microbial pollution builds up — and also by using monitors to track air after remediation, just as you might use a heart monitor to keep yourself healthy after a medical procedure.

Follow Didi Kirsten Tatlow on Twitter @dktatlow.