Why I Need to Keep Writing About Light Bulbs Instead of Something More Profound

I ran across this post the other day, while scrolling through some of the searches that have brought people to IA. It’s an example of why I’ve had to keep up my meager efforts to counteract factoids about compact fluorescent light bulbs. This individual was writing on the “American Thinker” blog, which from the other posts, apparently pulls quite a bit to the right politically. The post was pretty much the standard logic-deficient talking point from the right (mercury from CFLs is bad, therefore environmentalist positions on global climate change are bankrupt), but this time, ornamented with some really bad math:

A quick calculation shows that the 5 mg of mercury in an energy-conserving CFL is enough to fill an average size room (100 cubic meters volume) with the 0.05 mg/cubic meter vapor concentration that is considered hazardous for long term chronic exposure. Since this is the rule for laboratories, it probably does not account for people who might be especially sensitive, including infants, small children and pregnant women. As with allergies, different people can have vastly different responses to exposures to toxins.

The admonition to open the window for 15 minutes after a CFL break does not account for the various sizes / shapes of rooms, placement of windows (or absence thereof) and whether there is adequate cross-ventilation. And of course, it is not so convenient to ventilate a room thoroughly with outdoor air during the dead of winter in a northern clime.

Far be it from me to fuel a scare, but CFL backers are the global warming alarmists, after all, who have much less science to back up their claims for concern about climate change. It might be instructive to review the OSHA regulations concerning handling of mercury employed at CFL manufacturing plants. I bet the precautions are quite stringent.

No, no, no, no and no. Going back to the anecdote “all models are wrong, some are useful” (attributed to statistician George E.P. Box), the flaws in this particular model are: first, all of the mercury doesn’t volatilize in an instant, and second, it doesn’t volatilize into a hermetically sealed box. A few months back, I created an indoor air model of the concentrations in air you might expect if you broke a CFL in a room. It provides a more realistic depiction of the mass transfer of mercury from shimmering pinhead blob on the ground to vapor in air, and accounts, in a simple manner, typical air exchange in a room. I’m not going to insist this model is right, but EPA did calibrate it a bit using actual air monitoring data from other mercury spill situations (thermometers and ritual uses). And, I did obtain air concentrations thousands of times lower than American Thinker’s, which are not in the range considered hazardous for long-term chronic exposure. American Thinker’s cartoon depiction of indoor air modeling (no, strike that, my version is a cartoon depiction – his is a stick figure) reminds me of the IH classroom problem used to teach Ideal Gas Law calculations and dimensional analysis: “a 1-pound chlorine cylinder falls off a table in a closed 12 ft by 16 ft room with a 10 ft ceiling. The cylinder breaks and releases its contents instantaneously into the room. The air temperature is 77 degrees F. What is the chlorine concentration in air, in parts-per-million?” You don’t really use that kind of model for assessing exposures and health risks.

Guys, if you want to beat up “global warming alarmists”, just keep writing editorials. Please don’t try to inject facts into the discussion. You’ll only embarrass yourselves.

More Mercury Factoids: Compact Fluorescent Lightbulbs, Part 3 – Stop Reading Steven Milloy and Go Buy the Light Bulbs

Note: this is part of a series: earlier posts can be found here and here. I hope this is the last post I have to write on this topic. It truly is a non-issue. But I doubt that I’m going to be done with this any time soon.

If you’ve come searching for information on CFLs and mercury because you read an article by Steven Milloy (notorious for coining the term “junk science”, and no I’m not dignify his effluvium with a link from Impact Analysis) or a news article which quoted him uncritically, I’m not going to warn you to “consider the source”. Head over to PZ Myers if you want an opinion about the quality of Mr. Milloy “journalism”. However, if Steven Milloy is the one who got you all worried about this, let’s face it, you got owned. Read on, and you might be able to change that.

Mr. Milloy quotes two facts in his article – that the Maine Department of Environmental Protection (DEP) detected a mercury concentration in air 6-fold higher than a tolerable level in the bedroom of Ms. Brandy Bridges’s home, and that the DEP recommended she contact a cleanup contractor to mitigate the spill; the problem with a cleanup contractor is that they quoted Ms. Bridges a price of $2,000. Let’s start with the second one. Now the Ellsworth American news article that was the original source for this story also says that the DEP inspector recommended to Ms. Bridges that she didn’t attempt to clean up the spill, and call a cleanup contractor. The state’s version of the story was:

The homeowner expressed particular nervousness about exposures to mercury even in low numbers. Based on that concern, the responder explained two ways to minimize exposures to mercury: one way was to wear respiratory protection and another way was to hire a clean-up contractor. Since the homeowner did not have any respirator protection, the responder referred her to a commercial clean-up contractor. The responder further suggested that the homeowner talk with their homeowner’s insurance company to see if her policy would cover the cost of a professional clean-up contractor.

The DEP inspector also encouraged her to speak with a state toxicologist, who said that the potential mercury exposure was low and of negligible concern. As I’ve mentioned before, I don’t feel that Ms. Bridges got the best advice here, with regard to mitigation. Respiratory protection (i.e. wearing respirators) clearly wasn’t the right answer. Respirators are only for limited-duration use, involve professional judgment to select the proper type for a particular hazard, and require user training and fit-testing to be effective. However, telling someone who’s concerned about chemical exposure to simply not worry about it is generally ineffective. It is better if you can recommend that they take some kind of tangible action; it may not be necessary to reduce risks, and it may not have high effectiveness. What it accomplishes is to provide some sense of individual control over the situation, which is a factor in reducing anxiety and outrage over a health risk situation. Taking into consideration the air monitoring data collected by the state, a course of action that could have provided some benefit, could have given the homeowner the sense of managing the situation and would have been much cheaper than calling a cleanup contractor, would have been to go out to a home improvement store, buying a box fan, sticking it in a window, open a second window to provide some draft, and ventilating the room for a day.

Citing data selectively to make your point is a time-honored tactic of deception, and Mr. Milloy used it effectively here. Recall what was said in his news story:

The DEP sent a specialist to Bridges’ house to test for mercury contamination. The specialist found mercury levels in the bedroom in excess of six times the state’s “safe” level for mercury contamination of 300 billionths of a gram per cubic meter.

Dang, and I had just said I wasn’t going to link to him either. Oh, 300 billionths of a gram corresponds to 300 nanograms and, as discussed in a previous post, 300 nanograms per cubic meter of air is EPA’s Reference Concentration (RfC) for elemental mercury. Milloy’s screed about CFLs, global warming and environmentalists and their fruitcake ideas about mercury, all spring from this “fact”. Of course, it’s inaccurate and misleading, and one wonders why he even bothered citing it. As Ronald Reagan once said, “facts are stupid things”.

Ok, so there’s a real story here. Returning to the Maine DEP’s report:

When a Department responder goes to the site of a spill, there are typically two types of instrument measurements that they would take. The first is an evaluation of the source of the spill. This is to identify any hot spots or areas of concern, to determine the extent of the spill, and whether it has been tracked extensively throughout the home. This helps determine the extent of the effort to clean up the spill, if any. This type of measurement is generally at the floor or point of impact. The second type of measurement taken are those readings that are more useful for homeowner exposure and are typically in the “breathing zone”, at an intermediate height for children and a higher height more appropriate for adults.

When the Lumex mercury detector was positioned inches over the spill, the concentration detected was 1,939 ng/m3. The state’s report goes on to characterize this finding as follows:

Moving the Lumex instrument six to eight inches in either direction or up toward the ceiling dropped the value significantly. To visualize the area of high readings, it could be covered by a dinner plate.

So, for Mr. Milloy’s “fact” to really be correct, that the Maine DEP found mercury levels in the bedroom in excess of six times the state’s “safe” level for mercury contamination of 300 billionths of a gram per cubic meter, someone would have to crouch down onto the floor and inhale air from an area within six inches from the broken bulb. And they would have to do this daily for their entire lifetime to be exposed to a level six-fold higher than the safe level.

The state of Maine’s inspector also made some “breathing zone” measurements, sampling room air at a 3 foot level, which provides a better indication of the concentrations in air which someone might be breathing on a regular basis. Those concentrations were 31 and 49 ng/m3, which are less than the 300 ng/m3 RfC. In fact, most of the measurements were below 300 ng/m3, and the state’s report said,

Based upon this information, the State Toxicologist assured the homeowner that the potential mercury exposure would be very low and likely of negligible health concern.

But you don’t hear any of this from Mr. Milloy. At this point there’s only speculation as to why his readers weren’t given a more complete rendition of the facts. Perhaps it’s as creationist Duane Gish said during the McLean vs Arkansas Board of Education trial when accused of misquoting geological data refuting the creationist notion of a “young Earth”, “you have to stop quoting somewhere”.

I guess so. But at some point, you also have to stop listening to claptrap. You probably shouldn’t look to anything Steven Milloy says as a reason to not buy CFL bulbs.

More Mercury Factoids: Compact Fluorescent Light Bulbs, Part 2

Note: part of a series. Other posts are here and here.

So, why aren’t you going to get mercury poisoning if you break a CFL bulb in your home? First, it’s going to release only a very tiny amount of mercury into the air for a fairly limited period of time (as was discussed in the previous post). Second, we’re comparing that tiny amount of mercury in air with a health-based level that is highly protective - the Reference Concentration (RfC).

From studies of exposed human populations, it’s been observed that the most sensitive effects of low level exposure to elemental mercury occur in the nervous system. The most sensitive neurobehavioral effects were observed at levels in air as low as 25 ug/m3 (that’s microgram per cubic meter of air) with exposure occurring over a period of several years, as confirmed in multiple studies of exposed workers. This lowest-observe-adverse-level (LOAEL) is further reduced with uncertainty factors to protect sensitive individuals and to address where we don’t know much about inhaling elemental mercury (such as effects to the fetus from exposure to pregnant women, or to young children). The value you then get as the RfC is 0.3 ug/m3, which is about 100-fold below the level at which the most sensitive adverse effects have been observed with long-term inhalation exposure to mercury.

In addition, the definition of the RfC further confirms it’s protective nature:

In general, the RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily inhalation exposure of the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. (see Note 1, below)

Recall that I had done some calculations of mercury concentrations in air that could result from the emissions from breaking a CFL bulb indoors. The modeled concentrations rose to 0.48 ug/m3 after a day, and drop below the RfC (i.e. below 0.3 ug/m3) after three days, and remain below it all times after that (see Note 2, below). After three days, the modeled concentrations in air continue to decrease. They won’t go to zero, because that’s the nature of a model with an exponential term in it. However, for the folks who believe they need to have zero exposure to be “safe”, the 5 milligram mass of mercury that’s been released will eventually volatilize completely, and at some point in the future, the mercury concentrations in air will become undetectable (which is a little different than “zero”; sorry about that). Things should remain that way until the next time you break a bulb, which should be fairly infrequently (for myself, I try to not break light bulbs because I don’t like taking the risk of stepping in the broken glass).

So what about those couple of days where exposures are over the RfC? There isn’t a published health effects level covering that situation According to the ATSDR as with EPA, the LOAEL for less serious effects (i.e., the most sensitive effects) in humans were neurobehavioral effects such as tremors and poor performance in neurological testing observed at exposures ranging from 14 to 25 ug/m3 over a period more than half a year to 41 years (sorry it can’t be more precise, but that’s the nature of observational data). There’s lot’s of information about neurological effects in humans with high-level short duration inhalation exposure, but no exposure information. However, the levels in air producing adverse neurological effects in lab animals such as rats or rabbits typically are around 1,000 ug/m3 in air or higher for a period of days or weeks. Taking these things into consideration, along with the underlying philosophy that occasional exposures above the RfC don’t imply adverse effects are going to occur, it doesn’t appear that a few days of slightly elevated exposure to mercury vapor from breaking a CFL bulb would produce the shakes. This isn’t really a reason to not buy CFL bulbs. (For more information about mercury-related health effects, here’s the ATSDR public health statement).

As mentioned before, the RfC includes uncertainty factors to address what we don’t know yet about developmental effects to a fetus. This is prudent – in the ATSDR profile, there is one study with laboratory animals in which pregnant rats were exposed to 50 ug/m3 in air for a few hours a day over seven days, where the offspring exhibited neurological impairment. This is different from the other developmental studies in animals, in which short term exposures of ranging from 500 to 1,800 ug/m3 in air were producing neurobehavioral effects in the offspring, which is a thousand-fold higher than the short-term levels potentially associated with breaking a CFL bulb. As before, it doesn’t seem that a few days with slightly elevated exposures constitutes “appreciable risk of deleterious effects”. Not enough to require hiring a cleanup contractor if a bulb breaks in your house, and not enough to deter a reasonable person from buying CFL bulbs.

Note 1: the RfC isn’t a fixed line – above it you’re risking your health, below it you’re safe. It doesn’t work that way. Levels below it are unlikely to be associated with adverse health effects, and are considered protective and of no concern to regulatory agencies. However, as the magnitude and frequency (both are important) of exposure to levels above the RfC increases, the probability of adverse effects occurring increases. However you can’t say categorically that all levels of exposure below the RfC are safe, and that all levels above the RfC are associated with adverse health effects. Welcome to the real world of toxicology.

Note 2: no, I don’t know why the Ellsworth American and Steven Milloy said that the Maine DEP finding was the mercury level was in excess of six times the "EPA standard" in Ms. Bridges home. As typically occurs with the media reporting environmental stories, they didn’t provide enough information. Maybe the inspector made the measurements at carpet-level, while the EPA’s study (and the model) evaluated general room air. Maybe it’s because the inspector was making a measurement with a real-time instrument, and the level represents a short-term peak concentration, while the EPA’s study (and the model) are calculations of time-weighted average concentrations. I won’t speculate about quality control, instrument calibration or operator experience because that’s pointless, but these are also factors that affect the reliability of the measurements.

More Mercury Factoids: Compact Fluorescent Light Bulbs

Note: part of a series. Other posts on CFLs are here and here.

So I’m online getting some consumer information about compact fluorescent light (CFL) bulbs, the latest weapon in the war on carbon dioxide, and I happen to run across this tidbit published last month from the Junkman himself, Steven Milloy. Mr. Milloy has used the misfortune of one Maine woman, who broke a mercury-containing CFL bulb in her home and got a raft of really bad advice for what to do about it, as a springboard for bashing all environmentalists about reducing greenhouse gas emissions.

The news media had taken up the chase on this issue, and from them we find that the facts in this matter were as follows: According to an article in the Ellsworth American, Brandy Bridges dropped one of about two CFL dozen bulbs she was installing in her home, which broke on a shag carpet. Alert to the potential hazards of mercury exposure, Ms. Bridges called Home Depot, where she had bought the bulbs. Home Depot warned her not to vacuum the glass and directed her to a poison control hotline, which in turn referred her to the Maine Center for Disease Control and Prevention and the Maine Department of Environmental Protection. The DEP sent a specialist to test the mercury vapor levels in her home.

Here’s where the story starts to become fact-free: In her daughter's room near the broken bulb the mercury level was in excess of six times the EPA standard. This is completely accurate as far as the journalist knows – but at the same time, an utterly useless piece of information for trying to understand if there is a real health risk associated with a release of mercury from a broken CFL. Mr. Milloy gratuitously adds that the “safe” level for mercury is 300 billionth of a gram per cubic meter of air, a framing that tells you he really isn’t that concerned about the mercury exposure, but this was just too good an opportunity to pass up to beat up again on the folks who are concerned about global warming. I guess he doesn’t own any Philips stock.

Back to our story. DEP specialist told Ms. Bridges not to clean up the glass herself, but to call an environmental clean-up firm. The firm gave Ms. Bridges an estimate of $2,000 to clean up the broken bulb. Keep in mind this advice was completely inconsistent with the recommendations that EPA and many other regulatory agencies provide for disposal of broken bulbs. If anyone should be scraping together the money to deal with this, it should be the state of Maine, not Brandy Bridges.

The final irony in this misfortunate episode is that there probably was no real risk to begin with. Think about it for a moment. Mercury is a substance that requires cumulative exposure over a period of months or years to produce its adverse effects. And, a CFL contains around 5 milligrams of mercury, scarcely a pinhead’s-worth. No doubt that it will volatilize into a room, but how much mercury could that produce in the air, and for how long?

Quite a number of investigators have examined the problem of indoor air pollution from elemental mercury resulting from breaking mercury-containing thermometers, ritualistic uses and just playing around with mercury beads. In 2005, EPA published a series of studies examining mercury emissions and indoor concentrations under controlled conditions. I used the empirical model published in that report to estimate the air concentrations potentially associated with emissions of the 5 mg of mercury that would be released from breaking a CFL light bulb in a small bedroom under “average” air exchange conditions. The modeled mercury concentrations slightly exceed the “EPA standard” (the Reference Concentration, or RfC – which is not a standard, but that’s a story for another day) for a couple of days, but then drop below it, and fall well below it within two weeks. I hear the objections now, “but that’s not what the news story said”, but the factoid “six times higher than the EPA standard” is so poorly described and poorly informed, as to not even qualify as a factoid, and scarcely the basis for making environmental health decisions around CFL light bulbs. It’s certainly not persuading me to avoid using them.

Part 2 of this post coming to a blog near you discusses why being exposed for a couple of days to mercury concentrations in air higher than the RfC isn’t a public health problem, certainly not one warranting scaring people off from using CFL light bulbs. In addition, we can further discuss the matter of the choices we make to optimize environmental health and climate protection. But until then, don’t be afraid of CFL light bulbs because of the mercury in them (particularly if you’re getting the news from the Junk Science guy himself; consider the source).