Workers may be overexposed to silica.Logical formLearned from2 sentences. Silica may cause a (lung disease silicosis).Logical formLearned from2 sentences. Silica can be in samples.Logical formLearned from2 sentences. Samples may contain silica.Logical formLearned from2 sentences. A substance can be (silica compound).Logical formLearned from2 sentences. A (silica compound) may dry.Logical formLearned from2 sentences. Igneous rocks can be with silica.Logical formLearned from2 sentences. A (silica market) may pertain-to a continent.Logical formLearned from2 sentences. A (silica market) can be concentrated.Logical formLearned from2 sentences. A leader can be in a (silica market).Logical formLearned from2 sentences. Silica may take_on a color.Logical formLearned from2 sentences. Silicas may encase a microorganism.Logical formLearned from2 sentences. Silicas may spew.Logical formLearned from2 sentences. Chips can be constituted-of-or-filled-with silica.Logical formLearned from2 sentences. A (silica rulemaking) can be crystalline.Logical formLearned from2 sentences.