The ratings of 5 Chemicals stocks are down this week, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Slipping from a C to a D rating, Agrium Inc. (AGU) takes a hit this week. Agrium Inc. is a major retail supplier of agricultural products and services in the Americas, as well as a global producer and marketer of agricultural nutrients and industrial products. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings surprise, earnings momentum, and free cash flow. For more information, get Portfolio Grader’s complete analysis of AGU stock.

PPG Industries, Inc.’s (PPG) rating weakens this week, dropping to a F versus last week’s D. PPG Industries, Inc. supplies products for the manufacturing, construction, automotive, chemical processing, and other industries worldwide. The company also gets F’s in operating margin growth, earnings growth, and earnings momentum. For more information, get Portfolio Grader’s complete analysis of PPG stock.

Calgon Carbon Corporation (CCC) gets weaker ratings this week as last week’s C drops to a D. Calgon Carbon Corporation is engaged in products and services for purifying water and air. For more information, get Portfolio Grader’s complete analysis of CCC stock.

Flotek Industries, Inc. (FTK) is having a tough week. The company’s rating falls from a C to a D. Flotek Industries, Inc. manufactures and markets downhole equipment and specialty chemicals. The company also gets F’s in sales growth, operating margin growth, earnings growth, earnings revisions, and earnings surprise. For more information, get Portfolio Grader’s complete analysis of FTK stock.

BioAmber, Inc. (BIOA) declines this week from a C to a D. The company also gets F’s in earnings surprise, return on equity, and free cash flow. For more information, get Portfolio Grader’s complete analysis of BIOA 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.