Credit Suisse First Boston is working on a refinancing for Environmental Systems Products, a vehicle emissions and safety testing company. A buysider said the refinancing will enable the company to tender for preferred stock and refinance its capital structure, but CSFB bankers did not return calls and this could not be confirmed. A company spokeswoman also did not return calls by press time. The new credit is for up to $295 million and includes a $125 million, seven-year second-lien loan that is priced at LIBOR plus 61/2%. A five-year, first-lien loan is being shopped in the $125-150 million range with a spread of LIBOR plus 31/2%. A $20 million revolver is also priced at LIBOR plus 31/2% and has a 1% commitment fee.