Three service lines. One family.

ASAP Drug Solutions

A Unified Solution to Drug & Alcohol Testing and Employee Screening

Tried and tested by companies across America, ASAP’s comprehensive set of screening services can be tailored to meet the needs of your evolving workforce.


The Premier Occupational Healthcare Provider

Anywhere. Anytime. With caring medical providers and the latest technologies, CareOnSite is your best bet to keeping your workforce healthy and safe.


Tailored Instructor-Led and Computer-Based Safety Training

At OSCA, interactive training is best. When your workers are engaged and listening, we know they are going to be safer.

Our Approach

Our tailored services are based upon a set of principles that guide everything we do.

One Company - Three Services

We provide a diverse set of services dedicated to support all of your EH&S needs.

Industry Experience

We have decades of experience across several industries. We know your business.

Tailored Solutions

We customize our processes to meet your requirements.


We maintain the same high standards of quality across all our service lines

Clients Come First

We have no other stakeholders except our clients.

One Company - Three Services

Industry Experience

Tailored Solutions


Clients Come First

Industries We Serve

Companies acrossĀ a wide spectrum of industries have benefitedĀ from one or more of our services.
Oil & Gas
Offshore Oil

Why Us?

Who we are, how we grew and our commitment to excellence separate us from our competitors


Our story started in 1977, as a single medical clinic in Long Beach, CA. that was to become CareOnSite Medical Services.

Since then, we have grown into more than just a medical provider. In 1998, ASAP Drug Solutions was begun as a response to our clients’ drug-testing needs; then came OSCA in 2003, representing our foray into the safety training arena. We have also expanded our presence in the US, with offices in Carson, Martinez and Houston.

In 2016, our parent company Tang & Company was established, bringing the three separate businesses in our family – CareOnSite, ASAP and OSCA – under the same umbrella. The move has allowed us to create synergies among the businesses as we integrate our products, services, marketing strategies and corporate infrastructure, providing for our clients a truly one-stop shop solution for worker health, safety and security.


In industries across the nation every day, our highly skilled and caring team provides comprehensive healthcare, drug and alcohol program administration, compliance and safety training through integrated, value-based solutions customized to each client’s unique requirements.


Current Partners

Our clients are our partners.

Succeeding and growing together is the goal.

Let us know how we can be of service!