Maine lobstermen have spent a lot of time over the winter, spring and summer applying purple marks to their rope. The Department of Marine Resources has mandated that by September 1, all lobstermen, including those who fish gear in waters exempt from the federal whale plan, implement a new purple rope marking scheme to better identify the origin of any rope found on entangled right whales.
Few would think that handling dried rope while applying purple twine or paint in the paint shed could pose a health risk. But those ropes may be harboring an invisible menace.
Silicosis is a disease caused by inhalation of dust that contains bits of crystalline silica. Silica is a common mineral found in sand, quartz and many other types of rock. Over time, exposure to silica particles causes scarring in the lungs.
Those who work in boatyards can develop silicosis many years after initial exposure to silica dust. Workers who sandblast or use abrasives inadvertently may breath in high concentrations of silica dust, especially if they work in confined areas. The disease, which can cause shortness of breath, fatigue, chest pain, fever, and a persistent cough, is incurable.
Silica is also the basic element of a particular type of phytoplankton called diatoms. There is a vast number of species of photosynthesizing diatoms in the world’s oceans. They generate about 20% to 50% of the oxygen produced on the planet each year while absorbing huge amounts of silicon from seawater in order to create their skeletons. When diatoms die they settle to the ocean floor. Over the eons, great beds of dead diatoms have built up, many of which are now exposed on land. Diatomaceous earth, used by gardeners against slugs and as a pesticide, is made up of dried and compressed diatoms from long ago.
The problem with these particular forms of phytoplankton is that they are like glass. While strikingly beautiful seen under the microscope, the silica-based skeleton of a diatom has spikes, protuberances, and is generally a pretty scratchy item. Like most phytoplankton, diatoms may embed themselves in the ropes used by lobstermen at sea to attach their traps to the buoy or create trawls. When those ropes are brought ashore to dry, the diatoms dry on them as well. And that can be a problem for fishermen, who breathe in those diatoms when working through dried rope, particularly those who tend their gear while working within the confines of a small paint shed or shop.
Neither OSHA or the Northeast Center for Occupational Health and Safety have specific guidelines related to fishermen’s exposure to silica from diatoms. Common sense, however, suggests that working with dried rope would best be done out of doors, with plenty of ventilation. Silicosis is forever.