1. Carbon Monoxide office exposure during construction John S. Morawetz ICWUC Center for Worker Health and Safety Education JMorawetz@ICWUC.orgJMorawetz@ICWUC.org 513-621-8882 Summary A propane powered welding generator was used for construction purposes at a building that is occupied by a Training Center in Cincinnati, Ohio. Through the prompt use of a direct reading carbon monoxide (CO) meter, the staff was able to remove the source of the exposure and take rapid action to lower exposures to the staff. Exposure levels were recorded at various locations that demonstrate a wide variability of CO levels, some of which persisted for hours. Background Cincinnati, Ohio: Downtown 14 story office building ICWUC Center a tenant since 1988 Building sold in January, 2011 Landlord is converting floors 4 to 14 from offices to apartments

2. Loading Dock and Alley There was a history of diesel trucks in alley adjacent to loading dock. Basic Office Layout In the 1990s, Center staff had notified the previous building management about diesel emissions from the loading dock being noticeable inside the Center office space. This sign was subsequently posted in the alley adjacent to the loading dock.

3. Carbon Monoxide (CO) CO is a colorless, odorless and very toxic gas that is a common byproduct of incomplete combustion and improperly vented combustion devices. Unintentional and non–fire- related CO poisoning is responsible for more than 230,000 emergency department visits, 22,000 hospitalizations and approximately 450 deaths annually in the United States although rates appear to be falling recently. At lower levels of exposure, CO causes mild effects that are often mistaken for the flu (headaches, dizziness, disorientation, nausea and fatigue). January 5, 2012 Propane powered generator was needed for welding work. It was put on the loading dock with the door lowered but no venting. The temperature was app 23 over night; 30 during the AM. With Loading door open Door closed and location of generator Staff observed the generator on loading dock Staff retrieved CO direct reading instrument (GasAlertMicroClip XT; 4 gas detectors); range 0 – 500 ppm OSHA PEL 50 ppm -8-hour time-weighted average. NIOSH’s REL 35 ppm - 8-hour TWA and 200 ppm as a ceiling. ACGIH TLV 25 ppm - 8-hour workday.

4. Carbon Monoxide (CO) levels 10:45 AM Loading dock – 100 to 115 ppm 10:47 AM Generator turned off and moved to alley 10:50 AM 15 ppm – Instructor #1 office 25-30 ppm in Classroom 1 PM CO levels persisted 15 ppm – Instructor #1, 2 offices Management notified and expected appropriate steps to be taken to minimize/eliminate future exposures.

5. January 6, 2012 Generator on loading dock with door lowered Vented through flex hose under loading dock door CO on loading dock – 27 ppm at 11 AM Flex hose location Carbon Monoxide (CO) levels 11:00 AM Loading dock – 27 ppm Reception area – 15 ppm 11:05 AM 10-15 ppm – Instructor #1, #2 office 25 ppm in Classroom

6. Carbon Monoxide (CO) levels 11:15 AM 35-38 ppm around elevators OUTSIDE Office area This demonstrates the ability of CO to migrate to other areas. The elevators are outside the Center area but one level below ground as seen below. View from Center entrance along the long side of office area. Entrance is just above basement level but one level below ground at the classroom and rear elevators area. 11:18 AM Generator turned off and moved to alley Exterior Office door opened 11:35 AM 0 ppm - Reception area

7. Epilogue March 6, 2012 Staff noticed welding materials entering building Direct Reading unit turned on 2 nd floor: 27 ppm; recalibration indicator on It is discovered that generator is now operating in a construction room INSIDE the building on the first floor First Floor Layout 10:15 AM - Generator turned off Basement level monitored 10:45 - all 20 ppm Reception area, Elevator, Kitchen Hall Second floor – 10:50 am Office #3 – 11 ppm Office #4 – 22 ppm Hall – 22 ppm

8. 11 AM Generator moved to street with cables into the building. Exposures reduced but still significant Conclusions Significant exposures to a well known hazard continues to exist and OSHA standards may have been exceeded. CO danger from companies using propane generators not well addressed. CO can rapidly spread throughout office buildings.