Date: Mon, 11 Oct 2010 11:48:03 -0500
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: "Koster, Sandra" <koster.sand**At_Symbol_Here**UWLAX.EDU>
Subject: Re: Science Education & Safety - Follow-up
In-Reply-To: <62CF6C9F10C1D44DA44CCC3EE395B53F01E42CE592**At_Symbol_Here**N5AA20.okcu.edu>

I wonder if the student was attempting a transfer with a Pasteur pipet. Their intuition is to tip the pipet to keep the liquid from dripping which causes volatile liquids to immediately squirt out. They need to keep the pipet vertical with the dropper top up and opening down to minimize loss and have their receiving vessel right next to where they are using the pipet. If they just have to learn this by experience (even after being told) it's better if it isn't with methylene chloride. Sandra Koster On Mon, Oct 11, 2010 at 11:14 AM, Nail, John wrote: > "when a student received a few milliliters (of dichloromethane) squirt into > her nose" > > I assume that the 'squirt' was liquid and not vapor, which is VERY > different from the assumed original issue 'does the volatility and > respiratory exposure effects of dichloromethane make the respiration risks > from properly using dichloromethane too high to be acceptable?' > > Assuming that all dichloromethane transfers and handling were performed in > a hood with the sash at the proper position, students were properly handling > the dichloromethane, etc., this should not have occurred. > > I should note that organic solvents have viscosities that is much lower > than is water's; a consequence is that rough handling will result in > splashes that would not have occurred with water. Still, the hood sash > (assuming that the work was in a hood) should have functioned as a splash > barrier. > > One other possibility is the exposure was the result of a squeeze (wash) > bottle filled with dichloromethane. If so, eliminate wash bottles except for > DI water. > > -----Original Message----- > From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of > Russell Vernon > Sent: Monday, October 11, 2010 10:00 AM > To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU > Subject: [DCHAS-L] Science Education & Safety - Follow-up > > Thank you all for an insightful and informative discussion. I agree that we > should be teaching safety while we teach science (or chemistry in this > example) but alas I fear we could do much better. > > > > I asked for alternative extractions because I want to provide the faulty in > charge of this lab choices. > > Of course, one of the choices will be to continue with their existing > experiment, but with a heightened degree of hazard control. > > > > You see, I became aware of the use of dichloromethane when a student > received a few milliliters squirt into her nose, complained of breathing > difficulty and sought medical attention. > > > > As always there's more to the story but in my opinion the teaching lab does > not seem to be providing adequate ventilation control or administrative > control when this happens.... > > > > Sincerely, > > -Russ > > > > > > Russell Vernon, Ph.D. > > Research Safety > > Environmental Health & Safety > > University of California, Riverside > > 900 University Ave > > Riverside, CA 92521 > > www.ehs.ucr.edu > > russell.vernon**At_Symbol_Here**ucr.edu > > > > Direct (951) 827-5119 > > Admin (951) 827-5528 > > Fax (951) 827-5122 > > > >

I wonder if the student was attempting a transfer with a Pasteur pipet.=A0 Their intuition is to tip the pipet to keep the liquid from dripping which causes volatile liquids to immediately squirt out.=A0 They need to keep the pipet vertical with the dropper top up and opening down to minimize loss a nd have their receiving vessel right next to where they are using the pipet .=A0 If they just have to learn this by experience (even after being told) it's better if it isn't with methylene chloride.=A0

Sandra Koster=A0

On Mon, Oct 11, 201 0 at 11:14 AM, Nail, John <jnail**At_Symbol_Here**okcu.edu> wrote:
"when a student received a few milliliters (of dichloromethane) squirt into her nose"

I assume that the 'squirt' was liquid and not vapor, which is VERY< br> different from the assumed original issue 'does the volatility and resp iratory exposure effects of dichloromethane make the respiration risks from properly using dichloromethane too high to be acceptable?'

Assuming that all dichloromethane transfers and handling were performed in a hood with the sash at the proper position, students were properly handlin g the dichloromethane, etc., this should not have occurred.

I should note that organic solvents have viscosities that is much lower tha n is water's; a consequence is that rough handling will result in splas hes that would not have occurred with water. Still, the hood sash (assuming that the work was in a hood) should have functioned as a splash barrier.
One other possibility is the exposure was the result of a squeeze (wash) bo ttle filled with dichloromethane. If so, eliminate wash bottles except for DI water.


-----Original Message-----
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of Russell Vernon
Sent: Monday, October 11, 2010 10:00 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Science Education & Safety - Follow-up

Thank you all for an insightful and informative discussion. I agree that we
should be teaching safety while we teach science (or chemistry in this
example) but alas I fear we could do much better.

I asked for alternative extractions because I want to provide the faulty in
charge of this lab choices.

Of course, one of the choices will be to continue with their existing
experiment, but with a heightened degree of hazard control.

You see, I became aware of the use of dichloromethane when a student
received a few milliliters squirt into her nose, complained of breathing
difficulty and sought medical attention.

As always there's more to the story but in my opinion the teaching lab does
not seem to be providing adequate ventilation control or administrative
control when this happens....

Sincerely,

-Russ

Russell Vernon, Ph.D.

Research Safety

Environmental Health & Safety

University of California, Riverside

900 University Ave

Riverside, CA 92521

=A0<http://www.ehs. ucr.edu> www.eh s.ucr.edu

=A0<mailto:russell.vernon**At_Symbol_Here**ucr. edu> russell.vernon**At_Symbol_Here**ucr.ed u

Direct (951) 827-5119

Admin (951) 827-5528

Fax (951) 827-5122


--20cf30334ed1b3629e04925a1fc1--

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