Thursday, June 22, 2006

Pushing OR to See the Light, From Those Who Can't

It's been a very difficult year and a half for Sherry Rhoades, one of the teachers exposed to high intensity UV radiation from a broken metal halide bulb, at a conference in a Lake Oswego elementary school gym. The pain is constant, and the sensitivity to light strong. On Tuesday, the women--backed by Tualatin state Senator Richard Devlin--regathered in the same Bryant gym to tell their stories and urge the state to become serious about the dangers of the commonly used lights among governments, particularly schools.

What are metal halide lights? Here's a good description:
In striving for adequate lighting levels with cost-efficiency, many industrial and storage facilities have found high intensity discharge (HID) lighting to be advantageous. Most new manufacturing and storage buildings use this type of lighting, and many older buildings are being retrofitted with these types of fixtures and lamps.

HID lamps have a gas-filled quartz or ceramic arc tube, surrounded by an outer glass envelope or bulb. Light is emitted when an electrical current is applied between two tungsten electrodes inside the arc tube. The flow of current across the electrodes creates an arc which vaporizes the metallic contents inside the arc tube, raising the temperature and pressure inside the tube, with visible light emitted.

Lamps or bulbs of this type include mercury vapor, sodium vapor (both low & high pressure), and more recently metal halide...metal halide lamps produce a color that most people find acceptable for interior lighting, at close to the efficiency of mercury or sodium vapor bulbs.
Note the references to energy efficiency and new retrofits of old fixtures. Indeed, it's been considered green in Oregon--by advocates and executives alike--to switch over to HID lamps, particularly metal halide. They burn with a broad, bright light that makes them perfect for large indoor spaces, like gyms.

But what isn't often discussed about them is their potential danger:
While metal halide lamps solve a color balance problem, they are a potential ignition problem. The pressure inside the arc tube may reach 70 to 90 psi, and temperatures near 2000 F, both significantly above the temperature & pressure of sodium or mercury vapor lamps. Failure of the quartz or ceramic tube can permit hot fragments to fall. If the fixture does not have something to catch these hot fragments, they can be expected to land on combustible materials, with an ignition likely to occur. If employees are working directly beneath one of these fixtures at the time a violent failure occurs, the falling hot fragments could cause a burn injury.{emph mine}

Lamp failure can occur spontaneously, particularly as the bulb ages, or it could occur from the fixture or lamp being struck by an object such as a lift truck moving stock. The causes of spontaneous failures are not well established. Variations in product quality of lamp components is one theory, while certainly temperature extremes from improper lamp use or incorrect product selection are a possibility.

HID lighting devices (fixtures) are recognized by the National Electrical Code (NFPA 70) and listed by Underwriters Laboratories (UL), Inc. However, the main thrust of their efforts is in seeing that the fixtures are properly installed for the intended use, and that the ongoing operating temperatures of the devices do not set fire to nearby combustibles. The issue of a fire ignition from a lamp failure has yet to be addressed. UL's standards at this time do not test lamp failure modes. Nor does UL test every HID lighting fixture manufactured today; It is possible to purchase HID fixtures which are not UL listed. {emph me again}
Here, as so often we humans are prone to do, we have made the aesthetic, feel-good choice over the more efficient, safer one. There are cooler burning, cheaper, safer HID bulbs out there--but we don't like how we look under them. So we use metal halide, and we whistle past the graveyard on its safety, even as we install them in our schools.

The accident at Bryant was shocking even at first, but it became something of an outrage when the predicted fading of effects from the exposure did not happen. It appears that at least some of the women have suffered permanent or at minimum long-term damage. And after the accident became reported around the state, at least one other case, in a Douglas County middle school in 2000, had surfaced. Five years had gone by, and it's unclear whether any district grounds staff anywhere in the state have had any reaction to what has happened--either then, or now. Oregon OSHA put out a bulletin warning of the dangers, but left them on a website and encouraged people to spread the word themselves.

So what's been the upshot? I would be surprised if any school district in the state had done a comprehensive review of their lighting inventory and monitored their use of metal halide since the Lake Oswego accident, much less taken the recommended step of replacing the bulbs with models that would burn out immediately if the protective cover failed.

Which is where Devlin comes in. He recommends the state be willing to pay for replacements if the manufacturer will not exchange them for newer, non-extinguishing models. And he further wants to try exempting metal halide manufacturers from liability shielding based on a statute of limitations. That's not something that's going to happen in a 2007 legislature where the Republicans still hold the House, so be warned. Are your kids and teachers being needlessly exposed to potential threats from radiation and fire? And if so, why? What IS the official response in Salem to this issue? Does it even register? Here's hoping Devlin not only registers it but passes his proposals through the favorable Senate, and then pressures the House to follow suit.

Update, 2pm--
I guess The O's editorial board thought the same thing as I did, because they made largely the same points and call to action this morning. There are a couple of things in their story that are useful; they list the website put together by one of the victims and her husband: The O also indicates that some school districts have, in fact, taken steps to review their lighting inventory and replace some of their stock--among them, Beaverton and West Linn/Wilsonville. Good for them.