The key purpose of third party certified EMS standards is to allow buyers to have some assurance that their suppliers are in compliance with environmental laws and not taking on excessive environmental risks. Many leading buyers require their key suppliers to attain ISO 14001 for their manufacturing plants as pre-selection step. They may also conduct their own audits of the manufacturing sites of their most important suppliers. ISO 14001 has been criticised as being merely a documentation system and while a company’s standard is audited by a certified third party, the focus is on assessing documentation. As such many buyers have additional requirements, sometimes sector specific EMS standards or their own requirements such as Walmart’s environmental guide to suppliers. A secondary role of certification is to enhance the reputation of the company and act as a promotional tool. This is somewhat effective in selling the company to new buyers in the B2B supply chain, but this and other EMS standards have almost no recognition with individual consumers. Further, ISO 14001, due to its ubiquitous nature, is eyed with suspicion by many leading environmental NGOs when companies use it for promotional purposes.

The ISO series of environmental standards are the defacto, must-have standards in the global marketplace. As with other ISO standards they tend to be more important to global trade than to US domestic trade, where compliance standards are much stricter. As of 2007 there were at least 950,000 ISO 14001 certificates (and growing) issued in 175 countries around the world. Other EMS standards tend to be limited to specific sectors or product areas (e.g. Green Office) or very limited geographic regions (e.g. Hong Kong). A list of some of these on ekobai.com’s database is provided.