B.P. Richfield is a triceratops and Earl Sinclair's tyrannical field boss at the WESAYSO Development Corporation. Richfield is known for his fierce temper and tendency to eat those who quarrel with him (and also daughter Wendy Richfield's boyfriends as revealed in "Hungry for Love"). He seldom ventures outside of his trailer, overlooking the job site where Earl and his fellow tree pushers toil.
In the episode "Earl's Big Jackpot," which featured Richfield's mother, it was revealed that the initial "B" in Richfield's name stands for "Bradley." Other known relatives include a nephew (whose head was bitten off by Richfield) and an unseen wife. Richfield recalls the joy he felt when pushing his mother-in-law over a cliff on Hurling Day.
His last name, Richfield, is derived from the Richfield Oil Company, while his first two initials are taken from British Petroleum, another gas company.
B.P. Richfield is the most frequently recurring antagonist of the show whose selfish desires either mostly concerning finances and keeping WESAYSO out of trouble often put Earl Sinclair into many conflicts that affects him and his family.
- The Mighty Megalosaurus: After refusing to give Earl a raise, Richfield claims Earl must blame his family for their financial issues.
- Endangered Species: Threatens Earl to give him the Grapdelites so he can eat them or else he would bite off Earl's head. After Earl warned him they are the only ones left, Richfield pretended he agreed to conserve them but after Earl left he immediately ate them.
- Career Opportunities: Tries to eat Robbie as revenge for telling Richfield how to boss around the workers and forces Earl to come on weekends to practice root pulling while wearing a woman's fashion hat.
- Refrigerator Day: Doesn't give Earl his raise for Refridgerator Day, leading to the Sinclairs to starve.
- What "Sexual" Harris Meant: Defended the WESAYSO corporation as defendants against Monica DeVertebrae who was suing Al Sexual Harris.
- Power Erupts: Discredits Robbie for his volcano science project that provides power for households from volcanoes in order to keep the financial flow for WESAYSO.
- A New Leaf: Fires Earl for being annoying and 4 hours late. (Richfield claimed he wanted to kill Earl and his entire family, but decides not to because he would run into legal problems).
- Nuts to War: Tries to make an advertising campaign on WE ARE RIGHT (W.A.R.) to earn cash.
- And the Winner Is: Tried to become Chief Elder in order to reduce employee wages down to 2 cents a day and put almost every dinosaur bankrupt and homeless while demanding Earl to be the opponent candidate and lose.
- WESAYSO Knows Best: Replaces Earl with Roy as the head of the Sinclair family.
- Baby Talk: Kicked Earl extremely hard as revenge for Baby Sinclair calling him a "smoo".
- The Discovery: Marked territory onto the undiscovered lands Earl found in order to make money.
- Hungry for Love: Wanted to eat Robbie believing he dumped his daughter Wendy.
- Green Card: Fired all his tree-pushers because there were no trees left and refused to give Roy his job back for marrying a four-legger (Monica).
- If I Were A Tree: Ordered Sid Turtlepuss and Gus Molehill to destroy the tree containing Earl's soul with dynamite.
- Earl, Don't Be A Hero: Blackmails Earl into using his superpowers in advantage of advertising for WESAYSO as the superhero Captain Impressive or else he'll reveal his secret identity.
- Earl's Big Jackpot: Fires Earl for not being able to come to work due to a broken foot when Richfield forces all the tree-pushers to do overtime work. Then after Earl wins the lawsuit and gets $800 million out of WESAYSO, Richfield raises all prices on every consumer goods in order to redeem the financial loss of the company. When Robbie tries to return back the money, Earl accidentally bumps slightly into Richfield's trailer with his golf cart, then Richfield pretends to have a whiplash and sues the Sinclair family, but at court is forced to hire back all employee and lower all prices on consumer goods.
- Working Girl: Fires Charlene Sinclair for her superior performance as tree-pusher manager because then she would have her job for more than 6 years.
- Variations on a Theme Park: Builds a theme park that has high prices and additional fees on everything and doesn't put in any effort to build WESAYSO Land in order to save and raise money.
- Episode 101: The Mighty Megalosaurus
- Episode 103: Hurling Day
- Episode 205: Endangered Species
- Episode 206: Employee of the Month
- Episode 208: Career Opportunities
- Episode 212: Refrigerator Day
- Episode 213: What "Sexual" Harris Meant
- Episode 214: Fran Live
- Episode 215: Power Erupts
- Episode 217: A New Leaf
- Episode 219: Nuts to War (part 1)
- Episode 220: Nuts to War (part 2)
- Episode 221: And the Winner Is...
- Episode 224: WESAYSO Knows Best
- Episode 303: Baby Talk
- Episode 305: The Discovery
- Episode 308: Hungry for Love
- Episode 314: Green Card
- Episode 319: If I Were a Tree
- Episode 320: We Are Not Alone
- Episode 402: Earl, Don't Be a Hero
- Episode 403: The Greatest Story Ever Sold
- Episode 405: Earl's Big Jackpot
- Episode 407: Changing Nature
- Episode 410*: Working Girl
- Episode 411*: Variations on a Theme Park
- Episode 412*: Life in the Faust Lane