This week, the ratings of 5 Chemicals stocks on Portfolio Grader are down. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

This is a rough week for Ecolab Inc. (ECL). The company’s rating falls to D from the previous week’s C. Ecolab Inc. develops and markets products and services for the hospitality, foodservice, healthcare, and industrial markets primarily in the United States. For more information, get Portfolio Grader’s complete analysis of ECL stock.

PPG Industries, Inc. (PPG) gets weaker ratings this week as last week’s C drops to a D. PPG Industries, Inc. supplies products for the manufacturing, construction, automotive, chemical processing, and other industries worldwide. For more information, get Portfolio Grader’s complete analysis of PPG stock.

Slipping from a C to a D rating, FutureFuel Corp. (FF) takes a hit this week. FutureFuel Corp. produces biobased products, including biofuels, and biobased specialty products. The company also gets F’s in sales growth. For more information, get Portfolio Grader’s complete analysis of FF stock.

Senomyx, Inc. (SNMX) is having a tough week. The company’s rating falls from a C to a D. Senomyx, Inc. discovers new proprietary flavor and fragrance molecules for use in a wide range of consumer products. The company also gets F’s in return on equity. For more information, get Portfolio Grader’s complete analysis of SNMX stock.

This week, TerraVia Holdings, Inc. (TVIA) drops from a C to a D rating. The company also gets F’s in sales growth and free cash flow. For more information, get Portfolio Grader’s complete analysis of TVIA stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.