Tag: physical hazards

General physical hazards information

Inert gases and hypoxia in the lab

Inert gases such as nitrogen and argon are commonly used in our laboratories. If the contents of a cylinder were suddenly released into the laboratory atmosphere, the oxygen content of the air could be reduced below the safe 19.5% level necessary to avoid hypoxia in lab occupants.

Find out how to determine if a worst-case release of inert gas can reduce oxygen concentrations below safe levels and what you can do about the risk in this Safety Note: Inert Gas Safety.

Situational awareness

Situational awareness is having a “feel” for what’s going on around you—both the current state and how it might or will change in the near future. It’s a complicated topic (refer to Wikipedia for an introduction), but not having it can easily lead to incidents. I had a close call last year that occurred because I lost situational awareness.

I was photographing a worksite for a charity that recruits teams from disparate Howard County organizations varying from the County Police to church groups to employees of a well-known think tank to perform necessary repairs at the homes of the elderly and needy. It was at the latter’s “project house” that I almost got my brains knocked out.

The workers had removed a wheelbarrow full of soil from the yard while installing a new walkway, and they had procured a trailer to haul the soil and other debris away to the county landfill. I was standing at the front of the trailer taking pictures when the team hoisted the heavy wheelbarrow onto the trailer—setting it behind the axle. The resultant forces flipped the front of the trailer upward, and the trailer tongue (the metal bit that attaches to the tow vehicle) missed me by inches.

I had lost situational awareness—I failed to predict exactly what state my surroundings were in and in particular failed to predict how they were about to change. One can attribute part of this close call to “photographer’s hubris,” that is, the feeling that when one is behind the lens, one is indestructible. The major thing I failed to note, though, is that “charity home improvements” really means “construction site operated by amateurs,” and that I should be on my guard for dangerous conditions.

How often have you lost situational awareness—in the lab or on the road, perhaps? What was the result—did you have a close call, were there no consequences, or was there some sort of incident? What was the deciding factor in what the consequences were—chance?

Remember that in the lab we are all amateurs—so keep an eye on what you and your labmates are doing at all times.

Embolisms from high-pressure gas

Using high-pressure air or gases to blow off or dry parts can create embolisms—small bubbles in the bloodstream that cause blockages—if the nozzle comes in contact with your body. The law requires that you use special nozzles designed to prevent this risk. Alternatively, the gas pressure may be limited to allow gas to be used safely to clean and dry parts. The Laboratory Safety Advocate’s office has developed an inexpensive kit to help. Learn more in High Pressure Blow-Off Gas.

Unattended experiments

Some experiments take time: hours, days, even weeks. This means that the experiment will be set up and running in the lab while you are not there. You have an ethical obligation to prevent harm to others in the lab by ensuring that they are aware of your experiment and its hazards. Make sure they know:

  • What the purpose of the experiment is;
  • To whom it belongs;
  • What behavior indicates that something has gone wrong; and
  • What to do if something does go wrong.

You could tell the members of the lab all that information, but some lab members might not be present and others will promptly forget. Depending on the lab’s occupants to “know what’s going on” is foolish—your colleagues may know the general type of research you do but they are not familiar with the details of all your experiments. Far better is to post the information so that anyone in the lab can easily see what your experiment is, how to identify abnormal situations, and what to do in that event.

A sample form is available for you to use directly or adapt to your lab’s needs. (The file is in Word format for easy modification.) The form is written to allow use in teaching as well as research labs. You should prepare two copies of the form: one to post near the experimental apparatus and one to post in a safe place (like on the door). In an emergency, no one may be willing to approach the apparatus to read the information sheet!

Protect your eyes from high-intensity light

Protect your vision when working with UV germicidal lamps; lasers; welding and arc lamps; or other highenergy light sources. Special goggles limit the amount of light that can reach your eyes and skinThe type and amount of protection depends on the frequency, nature, and intensity of light. Learn more in Light eye protection.

Protect your face with a face shield

When a hazard involves a lot of energy or aggressive chemicals, your face may be at risk as well as your eyes. Also, Z87.1 or Z81+ rated eye protection may not be adequate to protect your eyes, so additional protection might be prudent. If you could injure your face in an accident, use a face shield to protect your face – learn more in High energy facial protection.

Protect your eyes from physical hazards

Physical hazards require eye protection designed for physical hazards. Always wear safety glasses or goggles when working with manual or power tools that may produce small particles (e.g.sanding, milling, cutting, hammering, scraping, etc.); working with tools that can generate droplets or a strong (>20psi) fluidstream, whether the fluid is air, water, or something else; processes producing lots of dust or other particles in the air (e.g., blowing leaves or snow from the sidewalk). Learn more in Physical hazard eye protection.

Is your plastic gas tubing an over-inflated balloon?

Many labs use compressed gases, and often we use pressure regulators to step down the 2000-3000 psi in the cylinder to the use pressure. If the regulator can produce more than about 30 psi outlet, your plastic tubing might be in danger of rupture. Read more about how to fix this without buying a new $500 regulator in How to prevent plastic tubing rupture.

What eye protection do I use?

There are many different types of protective eyewear available, and each one is designed to protect against a different hazard. Having the wrong type of safety eyewear can be worse than not wearing eye protection at all. Learn about the basic types in Choosing eye protection.

This Hopkins Safety Note is the start of a series on eye protection, so look for future notes covering the different types in detail.