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 screening services are tailored to meet the needs of your evolving workforce.


The Premier Occupational Healthcare Provider

Anywhere. Anytime. Caring medical providers and cutting-edge technology means CareOnSite is your best bet for 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’ll be safer on the job.

Our Approach

Our tailored services are based on 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.

We customize our processes to meet your requirements.

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

A wide spectrum of industries trust our services to ensure their employees stay safe and compliant.
Oil & Gas
Offshore Oil

Why Us?

Who we are, how we got here, and our commitment to excellence – What separates us from our competitors.


Our story started in 1977 as a single medical clinic in Long Beach, CA. 40 years later, CareOnSite Medical Services is still physician-led, and has grown to hundreds of locations across the USA and 5 offices in: Long Beach, Torrance, Carson, and Martinez, California as well as Houston, Texas.

Along the way we’ve grown to become more than just a medical provider. In 1998, ASAP Drug Solutions was launched to support our clients’ drug-testing needs. Then in 2003, OSCA was founded to offer high-quality safety training to high-hazard industries.

The Tang & Company parent company brings these three businesses – CareOnSite, ASAP, and OSCA – under the same umbrella. This move has allowed us to integrate our products, services, and corporate infrastructure, providing a truly one-stop solution for worker health, safety, and security.


Here at Tang & Company, we are focused on providing customized solutions to keep your workforce healthy, safe, and compliant.

In industries across the nation every day, our highly skilled and caring team provides comprehensive healthcare, drug & alcohol program administration, and compliance & safety training through integrated, value-based solutions catered to meet the unique needs of each client.


Current Partners

Our clients are our partners.

Succeeding and growing together is the goal.

Let us know how we can be of service!