Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
Issue link: http://uscgproceedings.epubxp.com/i/264352
78 Proceedings Winter 2013–2014 Understanding Styrene What is it? Styrene is a synthetic, organic chemical that produces polymers, resins, and rubber compounds. It is an aro- matic, colorless to yellowish oily liquid with a sweet odor, when pure, and a sharp disagreeable odor when not pure. It is only slightly soluble in water at 300 parts per million (ppm); but it is toxic to aquatic organisms. Styrene has many uses. For example, it is an important feedstock, and manufacturers use it in many goods including automobiles, fiberglass boats, office equip- ment, kitchen appliances, toys, containers, and as poly- styrene for food packaging. It is typically transported in bulk. Styrene-based products display increased durability, high performance, manufacturing versatility, and low production costs. Styrene also offers improved sanita- tion and hygiene benef ts, plus the material is readily recyclable. However, before producing f nal commercial products, bulk styrene monomer transport must be care- fully monitored and managed. Why should I care? Shipping concerns Styrene contains a small concentration of inhibitor to prevent self-polymerization. At high temperatures, sty- rene may undergo rapid exothermic polymerization, which could rupture bulk cargo holds or piping. A ves- sel transporting bulk styrene must have a certif cate of inhibition on the bridge. Additionally, vessels equipped with cargo tank heating coils must blank them off prior to carrying styrene, and the Coast Guard must endorse the vessel's certif cate of inspection to carry it. Health concerns Styrene is irritating to the skin, eyes, and respiratory system. Its vapors are heavier than air and may cause drowsiness, dizziness, and lung damage. As an aromatic hydrocarbon, the smell of styrene can be detected at a very low concentration of 0.15 ppm. If one is exposed to styrene, quickly move to fresh air and wash any affected skin and clothing thoroughly with soap and water. Fire or explosion concerns Styrene has a f ash point of 90 °F and can readily form explosive vapor/air mixtures — even when inhibited, it is a highly reactive and volatile substance. When tem- peratures reach 125 °F, styrene can still polymerize exo- thermically and generate heat very rapidly, which can quickly auto-ignite the bulk styrene material. Therefore, great care should be taken to avoid temperatures higher than 77 °F, including any open f ame or any source of static discharge. As a heavy vapor, styrene can travel long distances and reach remote ignition sources — caus- ing f ashback f re danger. In the event of f re, use foam, dry chemical powder, or carbon dioxide to smother the f ames. What is the Coast Guard doing about it? The U.S. Coast Guard requires all tank vessels carry- ing styrene in bulk to be inspected in accordance with 46 CFR, Chapter I, Subchapter O — Certain Bulk Dan- gerous Cargos. More specif cally, barges carrying sty- rene in bulk are regulated under 46 CFR 151; whereas, self-propelled tank vessels carrying styrene in bulk are examined under 46 CFR 153. Also, regarding cargo com- patibility, styrene belongs to the USCG Compatibility Group No. 30 — Olef ns. In the event of a chemical spill, immediately call the U.S. Coast Guard National Response Center at (800) 424-8802. About the author: LCDR Gregory Crettol graduated from the University of Connecticut in 2013 with an M.S. in chemical engineering. He was previously stationed in Yorktown, Va., as the chief of the International Maritime Off cer's School. His f eld tours include supervisor of MSD Unalaska and senior marine safety inspector of Sector Seattle. LCDR Crettol received a direct commission in 1998, after graduating from Washington State Univer‑ sity with a B.S. in biochemistry and a B.S. in chemical engineering. Chemical of the Quarter by LCDR GREGORY CRETTOL U.S. Coast Guard Academy Science Department 78 Proceedings Winter 2013–2014 www.uscg.mil/proceedings Winter �2013_45.indd 78 2/10/14 9:32 AM