Document DD5w1jvVjY0Y4KxwROaDLE8Kn

conoco iusr v Dl)1 a r ic e s Interoffice Communication To From Dat* subject J. E. Cearley D. D. Palmer September 20, 1977 Boundary Redefinition - Benzene Restricted rc rc -4 O Introduction C1 2 $ TO -o C it OSHA adopted May 21, 1977, a benzene temporary standard requiring steps to limit employee exposure to benzene vapors to 1.0 ppm 8-hour time weighted average, and a ceiling of 5*0 ppm for any 15 minute period during an eight hour day. At adoption of the standard, we had three benzene restricted areas; that is, areas where admittance required special permission and/or proper respiratory equipment, namely: (1) Ethylene Unit Quench Settler (2) Steam Plant Loading Rack (During LAD Loading) (3) API Separator North of the Holding Pond The above areas were set-up under a previous standard (25 ppm benzene ceiling) and, therefore, needed their boundaries redefined. A portable trailer containing an environmental gas chromatographic system was used to monitor benzene vapor levels in the vicinity of each restricted area. Conclusions 1. Steam Plant Loading Rack Restricted Area - Under present conditions, enlarge ment of this area 30 feet in all direction^ except Uo feet eastward, will be necessary to assure benzene exposure levels less than 5 ppm (15 minute - TWA) The enlarged area would include both a portion of railroad track and holding pond ammonia addition facilities, creating entry problems, suggesting control of the escaping vapors a better alternative than area enlargement. 2. Ethylene Unit Quench Settler - Without containment of benzene vapors in this area, north and south restricted area boundaries should be relocated 25 feet further fran the settler blowdown pit. A problem arising fran enlarging this area would be the blocking of traffic on both streets running east and west in the vicinity of the settler. Data collected in close proximity of the settler blowdown pit, when the pit is temporarily covered with visqueen, indicate permanent sealing of said pit, and a general area clean-up would allow complete area de-regulation. The cover over the pit would need to be well maintained as escaping vapors often contain 2500 ppm benzene. MCD 000009461 j. E. Cearley Page 2 September 20, 1977 3. Steam Plant Loading Rack - Area monitoring during LAD tank truck loading operations failed to detect benzene levels above 5 ppm at regulated area boundaries. Obviously, however, introduction of product containing Uo-5C$ benzene into open tank trucks could allow standard non-compliance beyond the limits of the restricted area boundaries under certain weather conditions. Recommendations1 2 1. LCCP Engineering should examine the feasibility of covering both the API separator and the Quench settler blowdown pit. 2, Eliminate work within 75-100 feet of the Steam Plant Loading Rack Restricted Area during LAD Truck Loading as an added safety factor. Should further information be required,, please advise. D. D. Palmer Project Chemist Lake Charles Chemical Plant maa ec: RHj-DDZ-(PCG-RLP-BKD)-SFP-LBD MCD 000009462