Allen,
I'll let others respond to your direct questrions, but here's some medical toxicology input.
While much has been written about the metabolic conversion of methylene chloride to carbon monoxide after systemic absorption and liver metabolism, in most clinical cases the levels of carboxyhemoglobin have been relatively low and in general not life-threatening. The main medical hazard is methylene chloride's properties as an inhalational anesthetic with a very low therapeutic index, meaning that the dosde that will produce surgical anesthesia is very close to the dose that will cause cessation of respiratipons. Also, with prolonged skin contact, significant chemical skin injuries can occur.
It would be worthwhile to consider these factors in the spill response procedure you are developing. As above, I'll let others in the group give advice about building evacuation aqnd elevator shutdown.
Alan
Alan H. Hall, M.D.
Medical Toxicologist
Date: Tue, 17 Jul 2012 10:54:02 -0400
From: anniemi**At_Symbol_Here**MTU.EDU
Subject: [DCHAS-L] Methylene Chloride Spill Response
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
I'd like to get some feedback from those of you with chemical spill response backgrounds. Given a busy 7-story mixed classroom and laboratory building with a single central hallway running the full length of the building (long rectangular building), and someone spills four liters of methylene chloride on the hallway floor during regular business hours, right in front of the elevators - some of the liquid and much of the vapor is running down the elevator shaft. Is there anyone out there who would not immediately evacuate the building? Would you use the fire alarm pull station to initiate an evacuation? If not, would you take other immediate actions to shut down the elevators?
There are several other response actions that would, obviously, be taken but I'm mostly interested in the building evacuation and elevator aspect.
I'm working on a spill response procedure and would like to hear from others before I make a final recommendation.
--
Allen Niemi, PhD
Director
Occupational Safety and Health Services
Room 322 Lakeshore Center
Michigan Technological University
Phone:
906-487-2118Fax:
906-487-3048
